diff --git a/src/node/ui_interface.h b/src/node/ui_interface.h
--- a/src/node/ui_interface.h
+++ b/src/node/ui_interface.h
@@ -24,7 +24,7 @@
 class CClientUIInterface {
 public:
     /** Flags for CClientUIInterface::ThreadSafeMessageBox */
-    enum MessageBoxFlags {
+    enum MessageBoxFlags : uint32_t {
         ICON_INFORMATION = 0,
         ICON_WARNING = (1U << 0),
         ICON_ERROR = (1U << 1),
diff --git a/test/sanitizer_suppressions/ubsan b/test/sanitizer_suppressions/ubsan
--- a/test/sanitizer_suppressions/ubsan
+++ b/test/sanitizer_suppressions/ubsan
@@ -43,7 +43,6 @@
 implicit-integer-sign-change:compressor.h
 implicit-integer-sign-change:crypto/*
 implicit-integer-sign-change:key.cpp
-implicit-integer-sign-change:noui.cpp
 implicit-integer-sign-change:prevector.h
 implicit-integer-sign-change:protocol.cpp
 implicit-integer-sign-change:script/bitcoinconsensus.cpp