diff --git a/lcl/interfaces/gtk2/gtk2proc.inc b/lcl/interfaces/gtk2/gtk2proc.inc
index 2408407568..8ef6d84620 100644
--- a/lcl/interfaces/gtk2/gtk2proc.inc
+++ b/lcl/interfaces/gtk2/gtk2proc.inc
@@ -2149,6 +2149,28 @@ var
     // the gtk2 gtkentry handles the return key and emits an activate signal
     // The LCL does not use that and needs the return key event
     // => emulate it
+
+    // emulate VK_RETURN on GtkButton. issue #21483
+    if GtkWidgetIsA(TargetWidget, gtk_type_button) then
+    begin
+      if (gdk_event_get_type(AEvent) = GDK_KEY_RELEASE) and
+        (VKey = VK_RETURN) then
+      begin
+        FillChar(Msg, SizeOf(Msg), 0);
+        Msg.CharCode := VKey;
+        if SysKey then
+          Msg.msg := LM_SYSKEYUP
+        else
+          Msg.msg := LM_KEYUP;
+        Msg.KeyData := CommonKeyData or (Flags shl 16) or $0001 {TODO:  repeatcount};
+        // do not send next LM_CLICKED. issue #21483
+        g_object_set_data(PGObject(TargetWidget),'lcl-button-stop-clicked', TargetWidget);
+        NotifyApplicationUserInput(TControl(TargetObj), Msg.Msg);
+        DeliverKeyMessage(TargetObj, Msg);
+      end;
+
+    end else
+
     if (
         GtkWidgetIsA(TargetWidget, gtk_type_entry) or
         GtkWidgetIsA(TargetWidget, gtk_type_text_view)
diff --git a/lcl/interfaces/gtk2/gtk2wsstdctrls.pp b/lcl/interfaces/gtk2/gtk2wsstdctrls.pp
index 27fc2a09f2..eac314185a 100644
--- a/lcl/interfaces/gtk2/gtk2wsstdctrls.pp
+++ b/lcl/interfaces/gtk2/gtk2wsstdctrls.pp
@@ -2280,10 +2280,25 @@ var
 begin
   Result := CallBackDefaultReturn;
   if AInfo^.ChangeLock > 0 then Exit;
+
+   // do not send LM_CLICKED. issue #21483
+  if g_object_get_data(PGObject(AWidget),'lcl-button-stop-clicked') = AWidget then
+  begin
+    g_object_set_data(PGObject(AWidget),'lcl-button-stop-clicked', nil);
+    exit;
+  end;
   Msg.Msg := LM_CLICKED;
   Result := DeliverMessage(AInfo^.LCLObject, Msg) = 0;
 end;
 
+function Gtk2WSButtonPressedEvent(widget: PGtkWidget; event: pgdkEventButton; data: gPointer): GBoolean; cdecl;
+begin
+  Result := CallBackDefaultReturn;
+  // set to nil data if we pressed return before,
+  // otherwise LM_CLICKED won't trigger. issue #21483
+  g_object_set_data(PGObject(Widget),'lcl-button-stop-clicked', nil);
+end;
+
 procedure Gtk2WSButton_SizeAllocate(widget: PGtkWidget; allocation: PGtkAllocation; user_data: gpointer); cdecl;
 var
   xthickness, ythickness: gint;
@@ -2339,6 +2354,7 @@ class procedure TGtk2WSButton.SetCallbacks(const AGtkWidget: PGtkWidget;
 begin
   TGtk2WSWinControl.SetCallbacks(PGtkObject(AGtkWidget), TComponent(AWidgetInfo^.LCLObject));
   SignalConnect(AWidgetInfo^.CoreWidget, 'clicked', @Gtk2WSButton_Clicked, AWidgetInfo);
+  SignalConnect(AWidgetInfo^.CoreWidget, 'button-press-event', @Gtk2WSButtonPressedEvent, AWidgetInfo);
   SignalConnect(AWidgetInfo^.CoreWidget, 'size-allocate', @Gtk2WSButton_SizeAllocate, AWidgetInfo);
 end;