diff --git a/lcl/include/customnotebook.inc b/lcl/include/customnotebook.inc
index fa9c0a88d8..ac859b1ca5 100644
--- a/lcl/include/customnotebook.inc
+++ b/lcl/include/customnotebook.inc
@@ -851,7 +851,7 @@ begin
              (csDestroyingHandle in ControlState) then
           begin
             OldPageIndex := FPageIndex;
-            FPageIndex := NMHDR^.idfrom;
+            FPageIndex := PtrInt(NMHDR^.idfrom);
             if FPageIndex >= PageCount then
               FPageIndex := -1;
             //debugln(['TCustomNotebook.CNNotify ',DbgSName(Self),' A Old=',OldPageIndex,' fPageIndex=',fPageIndex,' FLoadedPageIndex=',FLoadedPageIndex]);
diff --git a/lcl/interfaces/qt/qtwidgets.pas b/lcl/interfaces/qt/qtwidgets.pas
index 3f7717e2ac..75641c1edd 100644
--- a/lcl/interfaces/qt/qtwidgets.pas
+++ b/lcl/interfaces/qt/qtwidgets.pas
@@ -6304,7 +6304,7 @@ begin
 
   Hdr.hwndFrom := LCLObject.Handle;
   Hdr.Code := TCN_SELCHANGE;
-  Hdr.idFrom := TQtTabWidget(LCLObject.Handle).GetLCLPageIndex(Index);
+  Hdr.idFrom := PtrUInt(TQtTabWidget(LCLObject.Handle).GetLCLPageIndex(Index));
   Msg.NMHdr := @Hdr;
   Msg.Result := 0;
   DeliverMessage(Msg);