Once more into the depths of hell... er, I mean fix a focus issue.

So the new steals-focus protection stuff works well when there's a
focused control, but not as well when there's a modal dialog up which
happens not to have a focused control (or worse, a focusable control).

This adds a second mechanism for also checking to see if a modal dialog
is up (something that wxWidgets, true to form, makes very difficult).

Fixes https://gitlab.com/kicad/code/kicad/issues/6520

common/widgets/ui_common.cpp

@@ -23,7 +23,8 @@
 #include <widgets/ui_common.h>
 
 #include <algorithm>
-#include <gal/color4d.h>
+#include <dialog_shim.h>
+#include <pgm_base.h>
 
 int KIUI::GetStdMargin()
 {
@@ -142,4 +143,10 @@ bool KIUI::IsInputControlFocused()
     wxDataViewCtrl*   dataViewCtrl = dynamic_cast<wxDataViewCtrl*>( focus );
 
     return ( textEntry || styledText || listBox || dataViewCtrl );
+}
+
+
+bool KIUI::IsModalDialogFocused()
+{
+    return Pgm().m_ModalDialogCount > 0;
 }