diff --git a/src/qt/forms/optionsdialog.ui b/src/qt/forms/optionsdialog.ui
index fea759dee..7c37b24ea 100644
--- a/src/qt/forms/optionsdialog.ui
+++ b/src/qt/forms/optionsdialog.ui
@@ -1,903 +1,903 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <ui version="4.0">
  <class>OptionsDialog</class>
  <widget class="QDialog" name="OptionsDialog">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>560</width>
     <height>440</height>
    </rect>
   </property>
   <property name="windowTitle">
    <string>Options</string>
   </property>
   <property name="modal">
    <bool>true</bool>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
     <widget class="QTabWidget" name="tabWidget">
      <property name="currentIndex">
       <number>0</number>
      </property>
      <widget class="QWidget" name="tabMain">
       <attribute name="title">
        <string>&amp;Main</string>
       </attribute>
       <layout class="QVBoxLayout" name="verticalLayout_Main">
        <item>
         <widget class="QCheckBox" name="bitcoinAtStartup">
          <property name="toolTip">
           <string>Automatically start %1 after logging in to the system.</string>
          </property>
          <property name="text">
           <string>&amp;Start %1 on system login</string>
          </property>
         </widget>
        </item>
        <item>
         <spacer name="horizontalSpacer_0_Main">
          <property name="orientation">
           <enum>Qt::Horizontal</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>40</width>
            <height>5</height>
           </size>
          </property>
         </spacer>
        </item>
        <item>
        <layout class="QHBoxLayout" name="horizontalLayout_Main_Prune">
         <item>
          <widget class="QCheckBox" name="prune">
           <property name="toolTip">
            <string>Disables some advanced features but all blocks will still be fully validated. Reverting this setting requires re-downloading the entire blockchain. Actual disk usage may be somewhat higher.</string>
           </property>
           <property name="text">
            <string>Prune &amp;block storage to</string>
           </property>
          </widget>
         </item>
         <item>
          <widget class="QSpinBox" name="pruneSize"/>
         </item>
          <item>
           <widget class="QLabel" name="pruneSizeUnitLabel">
            <property name="text">
             <string>GB</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
           </widget>
          </item>
          <item>
           <spacer name="horizontalSpacer_Main_Prune">
            <property name="orientation">
             <enum>Qt::Horizontal</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>40</width>
              <height>20</height>
             </size>
            </property>
           </spacer>
          </item>
         </layout>
        </item>
        <item>
         <widget class="QLabel" name="pruneWarning">
          <property name="text">
           <string>Reverting this setting requires re-downloading the entire blockchain.</string>
          </property>
          <property name="textFormat">
           <enum>Qt::PlainText</enum>
          </property>
         </widget>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_2_Main">
          <item>
           <widget class="QLabel" name="databaseCacheLabel">
            <property name="text">
             <string>Size of &amp;database cache</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>databaseCache</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QSpinBox" name="databaseCache"/>
          </item>
          <item>
           <widget class="QLabel" name="databaseCacheUnitLabel">
            <property name="text">
             <string>MiB</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
           </widget>
          </item>
          <item>
           <spacer name="horizontalSpacer_2_Main">
            <property name="orientation">
             <enum>Qt::Horizontal</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>40</width>
              <height>20</height>
             </size>
            </property>
           </spacer>
          </item>
         </layout>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_Main_VerifyLabel">
          <item>
           <widget class="QLabel" name="threadsScriptVerifLabel">
            <property name="text">
             <string>Number of script &amp;verification threads</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>threadsScriptVerif</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QSpinBox" name="threadsScriptVerif">
            <property name="toolTip">
             <string>(0 = auto, &lt;0 = leave that many cores free)</string>
            </property>
           </widget>
          </item>
          <item>
           <spacer name="horizontalSpacer_Main_Threads">
            <property name="orientation">
             <enum>Qt::Horizontal</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>40</width>
              <height>20</height>
             </size>
            </property>
           </spacer>
          </item>
         </layout>
        </item>
        <item>
         <spacer name="verticalSpacer_Main">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>20</width>
            <height>40</height>
           </size>
          </property>
         </spacer>
        </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tabWallet">
       <attribute name="title">
        <string>W&amp;allet</string>
       </attribute>
       <layout class="QVBoxLayout" name="verticalLayout_Wallet">
        <item>
         <widget class="QGroupBox" name="groupBox">
          <property name="title">
           <string>Expert</string>
          </property>
          <layout class="QVBoxLayout" name="verticalLayout_2">
           <item>
            <widget class="QCheckBox" name="coinControlFeatures">
             <property name="toolTip">
              <string>Whether to show coin control features or not.</string>
             </property>
             <property name="text">
              <string>Enable coin &amp;control features</string>
             </property>
            </widget>
           </item>
           <item>
            <widget class="QCheckBox" name="spendZeroConfChange">
             <property name="toolTip">
              <string>If you disable the spending of unconfirmed change, the change from a transaction cannot be used until that transaction has at least one confirmation. This also affects how your balance is computed.</string>
             </property>
             <property name="text">
              <string>&amp;Spend unconfirmed change</string>
             </property>
            </widget>
           </item>
          </layout>
         </widget>
        </item>
        <item>
         <spacer name="verticalSpacer_Wallet">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>20</width>
            <height>40</height>
           </size>
          </property>
         </spacer>
        </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tabNetwork">
       <attribute name="title">
        <string>&amp;Network</string>
       </attribute>
       <layout class="QVBoxLayout" name="verticalLayout_Network">
        <item>
         <widget class="QCheckBox" name="mapPortUpnp">
          <property name="toolTip">
           <string>Automatically open the Bitcoin client port on the router. This only works when your router supports UPnP and it is enabled.</string>
          </property>
          <property name="text">
           <string>Map port using &amp;UPnP</string>
          </property>
         </widget>
        </item>
        <item>
         <widget class="QCheckBox" name="allowIncoming">
          <property name="toolTip">
           <string>Accept connections from outside.</string>
          </property>
          <property name="text">
           <string>Allow incomin&amp;g connections</string>
          </property>
         </widget>
        </item>
        <item>
         <widget class="QCheckBox" name="connectSocks">
          <property name="toolTip">
           <string>Connect to the Bitcoin network through a SOCKS5 proxy.</string>
          </property>
          <property name="text">
           <string>&amp;Connect through SOCKS5 proxy (default proxy):</string>
          </property>
         </widget>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_1_Network">
          <item>
           <widget class="QLabel" name="proxyIpLabel">
            <property name="text">
             <string>Proxy &amp;IP:</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>proxyIp</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QValidatedLineEdit" name="proxyIp">
            <property name="minimumSize">
             <size>
              <width>140</width>
              <height>0</height>
             </size>
            </property>
            <property name="maximumSize">
             <size>
              <width>140</width>
              <height>16777215</height>
             </size>
            </property>
            <property name="toolTip">
             <string>IP address of the proxy (e.g. IPv4: 127.0.0.1 / IPv6: ::1)</string>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLabel" name="proxyPortLabel">
            <property name="text">
             <string>&amp;Port:</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>proxyPort</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLineEdit" name="proxyPort">
            <property name="minimumSize">
             <size>
              <width>55</width>
              <height>0</height>
             </size>
            </property>
            <property name="maximumSize">
             <size>
              <width>55</width>
              <height>16777215</height>
             </size>
            </property>
            <property name="toolTip">
             <string>Port of the proxy (e.g. 9050)</string>
            </property>
           </widget>
          </item>
          <item>
           <spacer name="horizontalSpacer_1_Network">
            <property name="orientation">
             <enum>Qt::Horizontal</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>40</width>
              <height>20</height>
             </size>
            </property>
           </spacer>
          </item>
         </layout>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_2_Network">
          <item>
           <widget class="QLabel" name="proxyActiveNets">
            <property name="text">
             <string>Used for reaching peers via:</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QCheckBox" name="proxyReachIPv4">
            <property name="enabled">
             <bool>false</bool>
            </property>
            <property name="toolTip">
             <string>Shows if the supplied default SOCKS5 proxy is used to reach peers via this network type.</string>
            </property>
            <property name="text">
             <string/>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLabel" name="proxyReachIPv4Label">
            <property name="text">
             <string>IPv4</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QCheckBox" name="proxyReachIPv6">
            <property name="enabled">
             <bool>false</bool>
            </property>
            <property name="toolTip">
             <string>Shows if the supplied default SOCKS5 proxy is used to reach peers via this network type.</string>
            </property>
            <property name="text">
             <string/>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLabel" name="proxyReachIPv6Label">
            <property name="text">
             <string>IPv6</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QCheckBox" name="proxyReachTor">
            <property name="enabled">
             <bool>false</bool>
            </property>
            <property name="toolTip">
             <string>Shows if the supplied default SOCKS5 proxy is used to reach peers via this network type.</string>
            </property>
            <property name="text">
             <string/>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLabel" name="proxyReachTorLabel">
            <property name="text">
             <string>Tor</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
           </widget>
          </item>
          <item>
           <spacer name="horizontalSpacer_2_Network">
            <property name="orientation">
             <enum>Qt::Horizontal</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>40</width>
              <height>20</height>
             </size>
            </property>
           </spacer>
          </item>
         </layout>
        </item>
        <item>
         <widget class="QCheckBox" name="connectSocksTor">
          <property name="toolTip">
           <string>Connect to the Bitcoin network through a separate SOCKS5 proxy for Tor hidden services.</string>
          </property>
          <property name="text">
           <string>Use separate SOCKS&amp;5 proxy to reach peers via Tor hidden services:</string>
          </property>
         </widget>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_3_Network">
          <item>
           <widget class="QLabel" name="proxyIpTorLabel">
            <property name="text">
             <string>Proxy &amp;IP:</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>proxyIpTor</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QValidatedLineEdit" name="proxyIpTor">
            <property name="minimumSize">
             <size>
              <width>140</width>
              <height>0</height>
             </size>
            </property>
            <property name="maximumSize">
             <size>
              <width>140</width>
              <height>16777215</height>
             </size>
            </property>
            <property name="toolTip">
             <string>IP address of the proxy (e.g. IPv4: 127.0.0.1 / IPv6: ::1)</string>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLabel" name="proxyPortTorLabel">
            <property name="text">
             <string>&amp;Port:</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>proxyPortTor</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLineEdit" name="proxyPortTor">
            <property name="minimumSize">
             <size>
              <width>55</width>
              <height>0</height>
             </size>
            </property>
            <property name="maximumSize">
             <size>
              <width>55</width>
              <height>16777215</height>
             </size>
            </property>
            <property name="toolTip">
             <string>Port of the proxy (e.g. 9050)</string>
            </property>
           </widget>
          </item>
          <item>
           <spacer name="horizontalSpacer_4_Network">
            <property name="orientation">
             <enum>Qt::Horizontal</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>40</width>
              <height>20</height>
             </size>
            </property>
           </spacer>
          </item>
         </layout>
        </item>
        <item>
         <spacer name="verticalSpacer_Network">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>20</width>
            <height>40</height>
           </size>
          </property>
         </spacer>
        </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tabWindow">
       <attribute name="title">
        <string>&amp;Window</string>
       </attribute>
       <layout class="QVBoxLayout" name="verticalLayout_Window">
        <item>
         <widget class="QCheckBox" name="hideTrayIcon">
          <property name="toolTip">
           <string>Hide the icon from the system tray.</string>
          </property>
          <property name="text">
           <string>&amp;Hide tray icon</string>
          </property>
         </widget>
        </item>
        <item>
         <widget class="QCheckBox" name="minimizeToTray">
          <property name="toolTip">
           <string>Show only a tray icon after minimizing the window.</string>
          </property>
          <property name="text">
           <string>&amp;Minimize to the tray instead of the taskbar</string>
          </property>
         </widget>
        </item>
        <item>
         <widget class="QCheckBox" name="minimizeOnClose">
          <property name="toolTip">
           <string>Minimize instead of exit the application when the window is closed. When this option is enabled, the application will be closed only after selecting Exit in the menu.</string>
          </property>
          <property name="text">
           <string>M&amp;inimize on close</string>
          </property>
         </widget>
        </item>
        <item>
         <spacer name="verticalSpacer_Window">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>20</width>
            <height>40</height>
           </size>
          </property>
         </spacer>
        </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tabDisplay">
       <attribute name="title">
        <string>&amp;Display</string>
       </attribute>
       <layout class="QVBoxLayout" name="verticalLayout_Display">
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_1_Display">
          <item>
           <widget class="QLabel" name="langLabel">
            <property name="text">
             <string>User Interface &amp;language:</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>lang</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QValueComboBox" name="lang">
            <property name="toolTip">
             <string>The user interface language can be set here. This setting will take effect after restarting %1.</string>
            </property>
           </widget>
          </item>
         </layout>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_2_Display">
          <item>
           <widget class="QLabel" name="unitLabel">
            <property name="text">
             <string>&amp;Unit to show amounts in:</string>
            </property>
            <property name="textFormat">
             <enum>Qt::PlainText</enum>
            </property>
            <property name="buddy">
             <cstring>unit</cstring>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QValueComboBox" name="unit">
            <property name="toolTip">
             <string>Choose the default subdivision unit to show in the interface and when sending coins.</string>
            </property>
           </widget>
          </item>
         </layout>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout_3_Display">
          <item>
           <widget class="QLabel" name="thirdPartyTxUrlsLabel">
            <property name="toolTip">
             <string>Third party URLs (e.g. a block explorer) that appear in the transactions tab as context menu items. %s in the URL is replaced by transaction hash. Multiple URLs are separated by vertical bar |.</string>
            </property>
            <property name="text">
             <string>&amp;Third party transaction URLs</string>
            </property>
            <property name="buddy">
             <cstring>thirdPartyTxUrls</cstring>
            </property>
           </widget>
          </item>
          <item>
-          <widget class="QLineEdit" name="thirdPartyTxUrls">
+          <widget class="QValidatedLineEdit" name="thirdPartyTxUrls">
            <property name="toolTip">
             <string>Third party URLs (e.g. a block explorer) that appear in the transactions tab as context menu items. %s in the URL is replaced by transaction hash. Multiple URLs are separated by vertical bar |.</string>
            </property>
            <property name="placeholderText">
             <string notr="true">https://example.com/tx/%s</string>
            </property>
           </widget>
          </item>
         </layout>
        </item>
        <item>
         <spacer name="verticalSpacer_Display">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>20</width>
            <height>40</height>
           </size>
          </property>
         </spacer>
        </item>
       </layout>
      </widget>
     </widget>
    </item>
    <item>
     <widget class="QFrame" name="frame">
      <layout class="QVBoxLayout" name="verticalLayout_Bottom">
       <item>
        <layout class="QHBoxLayout" name="horizontalLayout_Bottom">
         <item>
          <widget class="QLabel" name="overriddenByCommandLineInfoLabel">
           <property name="text">
            <string>Options set in this dialog are overridden by the command line or in the configuration file:</string>
           </property>
           <property name="textFormat">
            <enum>Qt::PlainText</enum>
           </property>
          </widget>
         </item>
         <item>
          <spacer name="horizontalSpacer_Bottom">
           <property name="orientation">
            <enum>Qt::Horizontal</enum>
           </property>
           <property name="sizeHint" stdset="0">
            <size>
             <width>40</width>
             <height>20</height>
            </size>
           </property>
          </spacer>
         </item>
        </layout>
       </item>
       <item>
        <widget class="QLabel" name="overriddenByCommandLineLabel">
         <property name="text">
          <string/>
         </property>
         <property name="textFormat">
          <enum>Qt::PlainText</enum>
         </property>
         <property name="wordWrap">
          <bool>true</bool>
         </property>
        </widget>
       </item>
      </layout>
     </widget>
    </item>
    <item>
     <layout class="QHBoxLayout" name="horizontalLayout_Buttons">
      <item>
       <layout class="QVBoxLayout" name="verticalLayout_Buttons">
        <item>
         <widget class="QPushButton" name="openBitcoinConfButton">
          <property name="toolTip">
           <string>Open the %1 configuration file from the working directory.</string>
          </property>
          <property name="text">
           <string>Open Configuration File</string>
          </property>
          <property name="autoDefault">
           <bool>false</bool>
          </property>
         </widget>
        </item>
        <item>
         <widget class="QPushButton" name="resetButton">
          <property name="toolTip">
           <string>Reset all client options to default.</string>
          </property>
          <property name="text">
           <string>&amp;Reset Options</string>
          </property>
          <property name="autoDefault">
           <bool>false</bool>
          </property>
         </widget>
        </item>
       </layout>
      </item>
      <item>
       <spacer name="horizontalSpacer_1">
        <property name="orientation">
         <enum>Qt::Horizontal</enum>
        </property>
        <property name="sizeHint" stdset="0">
         <size>
          <width>40</width>
          <height>48</height>
         </size>
        </property>
       </spacer>
      </item>
      <item>
       <widget class="QLabel" name="statusLabel">
        <property name="minimumSize">
         <size>
          <width>200</width>
          <height>0</height>
         </size>
        </property>
        <property name="font">
         <font>
          <weight>75</weight>
          <bold>true</bold>
         </font>
        </property>
        <property name="text">
         <string/>
        </property>
        <property name="textFormat">
         <enum>Qt::PlainText</enum>
        </property>
        <property name="wordWrap">
         <bool>true</bool>
        </property>
       </widget>
      </item>
      <item>
       <spacer name="horizontalSpacer_2">
        <property name="orientation">
         <enum>Qt::Horizontal</enum>
        </property>
        <property name="sizeHint" stdset="0">
         <size>
          <width>40</width>
          <height>48</height>
         </size>
        </property>
       </spacer>
      </item>
      <item>
       <layout class="QVBoxLayout" name="verticalLayout_4">
        <item>
         <spacer name="verticalSpacer">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>20</width>
            <height>40</height>
           </size>
          </property>
         </spacer>
        </item>
        <item>
         <layout class="QHBoxLayout" name="horizontalLayout">
          <item>
           <widget class="QPushButton" name="okButton">
            <property name="text">
             <string>&amp;OK</string>
            </property>
            <property name="autoDefault">
             <bool>false</bool>
            </property>
            <property name="default">
             <bool>true</bool>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QPushButton" name="cancelButton">
            <property name="text">
             <string>&amp;Cancel</string>
            </property>
            <property name="autoDefault">
             <bool>false</bool>
            </property>
           </widget>
          </item>
         </layout>
        </item>
       </layout>
      </item>
     </layout>
    </item>
   </layout>
  </widget>
  <customwidgets>
   <customwidget>
    <class>QValidatedLineEdit</class>
    <extends>QLineEdit</extends>
    <header>qt/qvalidatedlineedit.h</header>
   </customwidget>
   <customwidget>
    <class>QValueComboBox</class>
    <extends>QComboBox</extends>
    <header>qt/qvaluecombobox.h</header>
   </customwidget>
  </customwidgets>
  <resources/>
  <connections/>
 </ui>
diff --git a/src/qt/optionsdialog.cpp b/src/qt/optionsdialog.cpp
index 0418caeff..7e7dc28df 100644
--- a/src/qt/optionsdialog.cpp
+++ b/src/qt/optionsdialog.cpp
@@ -1,426 +1,461 @@
 // Copyright (c) 2011-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #if defined(HAVE_CONFIG_H)
 #include <config/bitcoin-config.h>
 #endif
 
 #include <qt/forms/ui_optionsdialog.h>
 #include <qt/optionsdialog.h>
 
 #include <interfaces/node.h>
 #include <netbase.h>
 #include <qt/bitcoinunits.h>
 #include <qt/guiconstants.h>
 #include <qt/guiutil.h>
 #include <qt/optionsmodel.h>
 #include <txdb.h>       // for -dbcache defaults
 #include <validation.h> // for DEFAULT_SCRIPTCHECK_THREADS and MAX_SCRIPTCHECK_THREADS
 
 #include <QDataWidgetMapper>
 #include <QDir>
 #include <QIntValidator>
 #include <QLocale>
 #include <QMessageBox>
 #include <QSystemTrayIcon>
 #include <QTimer>
 
 OptionsDialog::OptionsDialog(QWidget *parent, bool enableWallet)
     : QDialog(parent), ui(new Ui::OptionsDialog), model(nullptr),
       mapper(nullptr) {
     ui->setupUi(this);
 
     /* Main elements init */
     ui->databaseCache->setMinimum(MIN_DB_CACHE_MB);
     ui->databaseCache->setMaximum(MAX_DB_CACHE_MB);
     ui->threadsScriptVerif->setMinimum(-GetNumCores());
     ui->threadsScriptVerif->setMaximum(MAX_SCRIPTCHECK_THREADS);
     ui->pruneWarning->setVisible(false);
     ui->pruneWarning->setStyleSheet("QLabel { color: red; }");
 
     ui->pruneSize->setEnabled(false);
     connect(ui->prune, &QPushButton::toggled, ui->pruneSize,
             &QWidget::setEnabled);
 
 /* Network elements init */
 #ifndef USE_UPNP
     ui->mapPortUpnp->setEnabled(false);
 #endif
 
     ui->proxyIp->setEnabled(false);
     ui->proxyPort->setEnabled(false);
     ui->proxyPort->setValidator(new QIntValidator(1, 65535, this));
 
     ui->proxyIpTor->setEnabled(false);
     ui->proxyPortTor->setEnabled(false);
     ui->proxyPortTor->setValidator(new QIntValidator(1, 65535, this));
 
     connect(ui->connectSocks, &QPushButton::toggled, ui->proxyIp,
             &QWidget::setEnabled);
     connect(ui->connectSocks, &QPushButton::toggled, ui->proxyPort,
             &QWidget::setEnabled);
     connect(ui->connectSocks, &QPushButton::toggled, this,
             &OptionsDialog::updateProxyValidationState);
 
     connect(ui->connectSocksTor, &QPushButton::toggled, ui->proxyIpTor,
             &QWidget::setEnabled);
     connect(ui->connectSocksTor, &QPushButton::toggled, ui->proxyPortTor,
             &QWidget::setEnabled);
     connect(ui->connectSocksTor, &QPushButton::toggled, this,
             &OptionsDialog::updateProxyValidationState);
 
     /* Window elements init */
 #ifdef Q_OS_MAC
     /* remove Window tab on Mac */
     ui->tabWidget->removeTab(ui->tabWidget->indexOf(ui->tabWindow));
     /* hide launch at startup option on macOS */
     ui->bitcoinAtStartup->setVisible(false);
     ui->verticalLayout_Main->removeWidget(ui->bitcoinAtStartup);
     ui->verticalLayout_Main->removeItem(ui->horizontalSpacer_0_Main);
 #endif
 
     /* remove Wallet tab and 3rd party-URL textbox in case of -disablewallet */
     if (!enableWallet) {
         ui->tabWidget->removeTab(ui->tabWidget->indexOf(ui->tabWallet));
         ui->thirdPartyTxUrlsLabel->setVisible(false);
         ui->thirdPartyTxUrls->setVisible(false);
     }
 
     /* Display elements init */
     QDir translations(":translations");
 
     ui->bitcoinAtStartup->setToolTip(
         ui->bitcoinAtStartup->toolTip().arg(PACKAGE_NAME));
     ui->bitcoinAtStartup->setText(
         ui->bitcoinAtStartup->text().arg(PACKAGE_NAME));
 
     ui->openBitcoinConfButton->setToolTip(
         ui->openBitcoinConfButton->toolTip().arg(PACKAGE_NAME));
 
     ui->lang->setToolTip(ui->lang->toolTip().arg(PACKAGE_NAME));
     ui->lang->addItem(QString("(") + tr("default") + QString(")"),
                       QVariant(""));
     for (const QString &langStr : translations.entryList()) {
         QLocale locale(langStr);
 
         /** check if the locale name consists of 2 parts (language_country) */
         if (langStr.contains("_")) {
             /** display language strings as "native language - native country
              * (locale name)", e.g. "Deutsch - Deutschland (de)" */
             ui->lang->addItem(locale.nativeLanguageName() + QString(" - ") +
                                   locale.nativeCountryName() + QString(" (") +
                                   langStr + QString(")"),
                               QVariant(langStr));
         } else {
             /** display language strings as "native language (locale name)",
              * e.g. "Deutsch (de)" */
             ui->lang->addItem(locale.nativeLanguageName() + QString(" (") +
                                   langStr + QString(")"),
                               QVariant(langStr));
         }
     }
     ui->unit->setModel(new BitcoinUnits(this));
 
     /* Widget-to-option mapper */
     mapper = new QDataWidgetMapper(this);
     mapper->setSubmitPolicy(QDataWidgetMapper::ManualSubmit);
     mapper->setOrientation(Qt::Vertical);
 
     GUIUtil::ItemDelegate *delegate = new GUIUtil::ItemDelegate(mapper);
     connect(delegate, &GUIUtil::ItemDelegate::keyEscapePressed, this,
             &OptionsDialog::reject);
     mapper->setItemDelegate(delegate);
 
     /* setup/change UI elements when proxy IPs are invalid/valid */
     ui->proxyIp->setCheckValidator(new ProxyAddressValidator(parent));
     ui->proxyIpTor->setCheckValidator(new ProxyAddressValidator(parent));
     connect(ui->proxyIp, &QValidatedLineEdit::validationDidChange, this,
             &OptionsDialog::updateProxyValidationState);
     connect(ui->proxyIpTor, &QValidatedLineEdit::validationDidChange, this,
             &OptionsDialog::updateProxyValidationState);
     connect(ui->proxyPort, &QLineEdit::textChanged, this,
             &OptionsDialog::updateProxyValidationState);
     connect(ui->proxyPortTor, &QLineEdit::textChanged, this,
             &OptionsDialog::updateProxyValidationState);
 
+    /* setup/change UI elements when third party tx URLs are invalid/valid */
+    ui->thirdPartyTxUrls->setCheckValidator(
+        new ThirdPartyTxUrlsValidator(parent));
+    connect(ui->thirdPartyTxUrls, &QValidatedLineEdit::validationDidChange,
+            this, &OptionsDialog::updateThirdPartyTxUrlsState);
+
     if (!QSystemTrayIcon::isSystemTrayAvailable()) {
         ui->hideTrayIcon->setChecked(true);
         ui->hideTrayIcon->setEnabled(false);
         ui->minimizeToTray->setChecked(false);
         ui->minimizeToTray->setEnabled(false);
     }
 
     GUIUtil::handleCloseWindowShortcut(this);
 }
 
 OptionsDialog::~OptionsDialog() {
     delete ui;
 }
 
 void OptionsDialog::setModel(OptionsModel *_model) {
     this->model = _model;
 
     if (_model) {
         /* check if client restart is needed and show persistent message */
         if (_model->isRestartRequired()) {
             showRestartWarning(true);
         }
 
         // Prune values are in GB to be consistent with intro.cpp
         static constexpr uint64_t nMinDiskSpace =
             (MIN_DISK_SPACE_FOR_BLOCK_FILES / GB_BYTES) +
                     (MIN_DISK_SPACE_FOR_BLOCK_FILES % GB_BYTES)
                 ? 1
                 : 0;
         ui->pruneSize->setRange(nMinDiskSpace, std::numeric_limits<int>::max());
 
         QString strLabel = _model->getOverriddenByCommandLine();
         if (strLabel.isEmpty()) {
             strLabel = tr("none");
         }
         ui->overriddenByCommandLineLabel->setText(strLabel);
 
         mapper->setModel(_model);
         setMapper();
         mapper->toFirst();
 
         updateDefaultProxyNets();
     }
 
     /* warn when one of the following settings changes by user action (placed
      * here so init via mapper doesn't trigger them) */
 
     /* Main */
     connect(ui->prune, &QCheckBox::clicked, this,
             &OptionsDialog::showRestartWarning);
     connect(ui->prune, &QCheckBox::clicked, this,
             &OptionsDialog::togglePruneWarning);
     connect(ui->pruneSize,
             static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), this,
             &OptionsDialog::showRestartWarning);
     connect(ui->databaseCache,
             static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), this,
             &OptionsDialog::showRestartWarning);
     connect(ui->threadsScriptVerif,
             static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), this,
             &OptionsDialog::showRestartWarning);
     /* Wallet */
     connect(ui->spendZeroConfChange, &QCheckBox::clicked, this,
             &OptionsDialog::showRestartWarning);
     /* Network */
     connect(ui->allowIncoming, &QCheckBox::clicked, this,
             &OptionsDialog::showRestartWarning);
     connect(ui->connectSocks, &QCheckBox::clicked, this,
             &OptionsDialog::showRestartWarning);
     connect(ui->connectSocksTor, &QCheckBox::clicked, this,
             &OptionsDialog::showRestartWarning);
     /* Display */
     connect(
         ui->lang,
         static_cast<void (QValueComboBox::*)()>(&QValueComboBox::valueChanged),
         [this] { showRestartWarning(); });
     connect(ui->thirdPartyTxUrls, &QLineEdit::textChanged,
             [this] { showRestartWarning(); });
 }
 
 void OptionsDialog::setCurrentTab(OptionsDialog::Tab tab) {
     QWidget *tab_widget = nullptr;
     if (tab == OptionsDialog::Tab::TAB_NETWORK) {
         tab_widget = ui->tabNetwork;
     }
     if (tab == OptionsDialog::Tab::TAB_MAIN) {
         tab_widget = ui->tabMain;
     }
     if (tab_widget && ui->tabWidget->currentWidget() != tab_widget) {
         ui->tabWidget->setCurrentWidget(tab_widget);
     }
 }
 
 void OptionsDialog::setMapper() {
     /* Main */
     mapper->addMapping(ui->bitcoinAtStartup, OptionsModel::StartAtStartup);
     mapper->addMapping(ui->threadsScriptVerif,
                        OptionsModel::ThreadsScriptVerif);
     mapper->addMapping(ui->databaseCache, OptionsModel::DatabaseCache);
     mapper->addMapping(ui->prune, OptionsModel::Prune);
     mapper->addMapping(ui->pruneSize, OptionsModel::PruneSize);
 
     /* Wallet */
     mapper->addMapping(ui->spendZeroConfChange,
                        OptionsModel::SpendZeroConfChange);
     mapper->addMapping(ui->coinControlFeatures,
                        OptionsModel::CoinControlFeatures);
 
     /* Network */
     mapper->addMapping(ui->mapPortUpnp, OptionsModel::MapPortUPnP);
     mapper->addMapping(ui->allowIncoming, OptionsModel::Listen);
 
     mapper->addMapping(ui->connectSocks, OptionsModel::ProxyUse);
     mapper->addMapping(ui->proxyIp, OptionsModel::ProxyIP);
     mapper->addMapping(ui->proxyPort, OptionsModel::ProxyPort);
 
     mapper->addMapping(ui->connectSocksTor, OptionsModel::ProxyUseTor);
     mapper->addMapping(ui->proxyIpTor, OptionsModel::ProxyIPTor);
     mapper->addMapping(ui->proxyPortTor, OptionsModel::ProxyPortTor);
 
 /* Window */
 #ifndef Q_OS_MAC
     if (QSystemTrayIcon::isSystemTrayAvailable()) {
         mapper->addMapping(ui->hideTrayIcon, OptionsModel::HideTrayIcon);
         mapper->addMapping(ui->minimizeToTray, OptionsModel::MinimizeToTray);
     }
     mapper->addMapping(ui->minimizeOnClose, OptionsModel::MinimizeOnClose);
 #endif
 
     /* Display */
     mapper->addMapping(ui->lang, OptionsModel::Language);
     mapper->addMapping(ui->unit, OptionsModel::DisplayUnit);
     mapper->addMapping(ui->thirdPartyTxUrls, OptionsModel::ThirdPartyTxUrls);
 }
 
 void OptionsDialog::setOkButtonState(bool fState) {
     ui->okButton->setEnabled(fState);
 }
 
 void OptionsDialog::on_resetButton_clicked() {
     if (model) {
         // confirmation dialog
         QMessageBox::StandardButton btnRetVal = QMessageBox::question(
             this, tr("Confirm options reset"),
             tr("Client restart required to activate changes.") + "<br><br>" +
                 tr("Client will be shut down. Do you want to proceed?"),
             QMessageBox::Yes | QMessageBox::Cancel, QMessageBox::Cancel);
 
         if (btnRetVal == QMessageBox::Cancel) {
             return;
         }
 
         /* reset all options and close GUI */
         model->Reset();
         QApplication::quit();
     }
 }
 
 void OptionsDialog::on_openBitcoinConfButton_clicked() {
     /* explain the purpose of the config file */
     QMessageBox::information(
         this, tr("Configuration options"),
         tr("The configuration file is used to specify advanced user options "
            "which override GUI settings. Additionally, any command-line "
            "options will override this configuration file."));
 
     /* show an error if there was some problem opening the file */
     if (!GUIUtil::openBitcoinConf()) {
         QMessageBox::critical(
             this, tr("Error"),
             tr("The configuration file could not be opened."));
     }
 }
 
 void OptionsDialog::on_okButton_clicked() {
     mapper->submit();
     accept();
     updateDefaultProxyNets();
 }
 
 void OptionsDialog::on_cancelButton_clicked() {
     reject();
 }
 
 void OptionsDialog::on_hideTrayIcon_stateChanged(int fState) {
     if (fState) {
         ui->minimizeToTray->setChecked(false);
         ui->minimizeToTray->setEnabled(false);
     } else {
         ui->minimizeToTray->setEnabled(true);
     }
 }
 
 void OptionsDialog::togglePruneWarning(bool enabled) {
     ui->pruneWarning->setVisible(!ui->pruneWarning->isVisible());
 }
 
 void OptionsDialog::showRestartWarning(bool fPersistent) {
     ui->statusLabel->setStyleSheet("QLabel { color: red; }");
 
     if (fPersistent) {
         ui->statusLabel->setText(
             tr("Client restart required to activate changes."));
     } else {
         ui->statusLabel->setText(
             tr("This change would require a client restart."));
         // clear non-persistent status label after 10 seconds
         // TODO: should perhaps be a class attribute, if we extend the use of
         // statusLabel
         QTimer::singleShot(10000, this, &OptionsDialog::clearStatusLabel);
     }
 }
 
 void OptionsDialog::clearStatusLabel() {
     ui->statusLabel->clear();
     if (model && model->isRestartRequired()) {
         showRestartWarning(true);
     }
 }
 
 void OptionsDialog::updateProxyValidationState() {
     QValidatedLineEdit *pUiProxyIp = ui->proxyIp;
     QValidatedLineEdit *otherProxyWidget =
         (pUiProxyIp == ui->proxyIpTor) ? ui->proxyIp : ui->proxyIpTor;
     if (pUiProxyIp->isValid() &&
         (!ui->proxyPort->isEnabled() || ui->proxyPort->text().toInt() > 0) &&
         (!ui->proxyPortTor->isEnabled() ||
          ui->proxyPortTor->text().toInt() > 0)) {
         // Only enable ok button if both proxys are valid
         setOkButtonState(otherProxyWidget->isValid());
         clearStatusLabel();
     } else {
         setOkButtonState(false);
         ui->statusLabel->setStyleSheet("QLabel { color: red; }");
         ui->statusLabel->setText(tr("The supplied proxy address is invalid."));
     }
 }
 
 void OptionsDialog::updateDefaultProxyNets() {
     proxyType proxy;
     std::string strProxy;
     QString strDefaultProxyGUI;
 
     model->node().getProxy(NET_IPV4, proxy);
     strProxy = proxy.proxy.ToStringIP() + ":" + proxy.proxy.ToStringPort();
     strDefaultProxyGUI = ui->proxyIp->text() + ":" + ui->proxyPort->text();
     (strProxy == strDefaultProxyGUI.toStdString())
         ? ui->proxyReachIPv4->setChecked(true)
         : ui->proxyReachIPv4->setChecked(false);
 
     model->node().getProxy(NET_IPV6, proxy);
     strProxy = proxy.proxy.ToStringIP() + ":" + proxy.proxy.ToStringPort();
     strDefaultProxyGUI = ui->proxyIp->text() + ":" + ui->proxyPort->text();
     (strProxy == strDefaultProxyGUI.toStdString())
         ? ui->proxyReachIPv6->setChecked(true)
         : ui->proxyReachIPv6->setChecked(false);
 
     model->node().getProxy(NET_ONION, proxy);
     strProxy = proxy.proxy.ToStringIP() + ":" + proxy.proxy.ToStringPort();
     strDefaultProxyGUI = ui->proxyIp->text() + ":" + ui->proxyPort->text();
     (strProxy == strDefaultProxyGUI.toStdString())
         ? ui->proxyReachTor->setChecked(true)
         : ui->proxyReachTor->setChecked(false);
 }
 
 ProxyAddressValidator::ProxyAddressValidator(QObject *parent)
     : QValidator(parent) {}
 
 QValidator::State ProxyAddressValidator::validate(QString &input,
                                                   int &pos) const {
     Q_UNUSED(pos);
     // Validate the proxy
     CService serv(LookupNumeric(input.toStdString(), DEFAULT_GUI_PROXY_PORT));
     proxyType addrProxy = proxyType(serv, true);
     if (addrProxy.IsValid()) {
         return QValidator::Acceptable;
     }
 
     return QValidator::Invalid;
 }
+
+void OptionsDialog::updateThirdPartyTxUrlsState() {
+    QValidatedLineEdit *thirdPartyTxUrls = ui->thirdPartyTxUrls;
+    if (thirdPartyTxUrls->isValid()) {
+        // Only enable OK button if the third party tx URLS pattern is valid
+        setOkButtonState(true);
+        clearStatusLabel();
+    } else {
+        setOkButtonState(false);
+        ui->statusLabel->setStyleSheet("QLabel { color: red; }");
+        ui->statusLabel->setText(
+            tr("The third party transaction URLs should start with https://."));
+    }
+}
+
+ThirdPartyTxUrlsValidator::ThirdPartyTxUrlsValidator(QObject *parent)
+    : QValidator(parent) {}
+
+QValidator::State ThirdPartyTxUrlsValidator::validate(QString &input,
+                                                      int &pos) const {
+    Q_UNUSED(pos);
+    // Check the URL starts with https. All other schemes are rejected for
+    // security reasons.
+    if (input.isEmpty() || input.startsWith("https://")) {
+        return QValidator::Acceptable;
+    }
+
+    return QValidator::Invalid;
+}
diff --git a/src/qt/optionsdialog.h b/src/qt/optionsdialog.h
index 55c163836..86868ef29 100644
--- a/src/qt/optionsdialog.h
+++ b/src/qt/optionsdialog.h
@@ -1,75 +1,86 @@
 // Copyright (c) 2011-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_QT_OPTIONSDIALOG_H
 #define BITCOIN_QT_OPTIONSDIALOG_H
 
 #include <QDialog>
 #include <QValidator>
 
 class OptionsModel;
 class QValidatedLineEdit;
 
 QT_BEGIN_NAMESPACE
 class QDataWidgetMapper;
 QT_END_NAMESPACE
 
 namespace Ui {
 class OptionsDialog;
 }
 
 /** Proxy address widget validator, checks for a valid proxy address. */
 class ProxyAddressValidator : public QValidator {
     Q_OBJECT
 
 public:
     explicit ProxyAddressValidator(QObject *parent);
 
     State validate(QString &input, int &pos) const override;
 };
 
+/** Third party tx URL validator, checks for an https link. */
+class ThirdPartyTxUrlsValidator : public QValidator {
+    Q_OBJECT
+
+public:
+    explicit ThirdPartyTxUrlsValidator(QObject *parent);
+
+    State validate(QString &input, int &pos) const override;
+};
+
 /** Preferences dialog. */
 class OptionsDialog : public QDialog {
     Q_OBJECT
 
 public:
     explicit OptionsDialog(QWidget *parent, bool enableWallet);
     ~OptionsDialog();
 
     enum Tab {
         TAB_MAIN,
         TAB_NETWORK,
     };
 
     void setModel(OptionsModel *model);
     void setMapper();
     void setCurrentTab(OptionsDialog::Tab tab);
 
 private Q_SLOTS:
     /* set OK button state (enabled / disabled) */
     void setOkButtonState(bool fState);
     void on_resetButton_clicked();
     void on_openBitcoinConfButton_clicked();
     void on_okButton_clicked();
     void on_cancelButton_clicked();
 
     void on_hideTrayIcon_stateChanged(int fState);
 
     void togglePruneWarning(bool enabled);
     void showRestartWarning(bool fPersistent = false);
     void clearStatusLabel();
     void updateProxyValidationState();
     /* query the networks, for which the default proxy is used */
     void updateDefaultProxyNets();
+    void updateThirdPartyTxUrlsState();
 
 Q_SIGNALS:
     void proxyIpChecks(QValidatedLineEdit *pUiProxyIp, int nProxyPort);
 
 private:
     Ui::OptionsDialog *ui;
     OptionsModel *model;
     QDataWidgetMapper *mapper;
 };
 
 #endif // BITCOIN_QT_OPTIONSDIALOG_H