diff --git a/lcl/interfaces/qt/qtobject.inc b/lcl/interfaces/qt/qtobject.inc
index 4e602759c8..4ceb5751ac 100644
--- a/lcl/interfaces/qt/qtobject.inc
+++ b/lcl/interfaces/qt/qtobject.inc
@@ -622,7 +622,7 @@ end;
 function TQtWidgetSet.EventFilter(Sender: QObjectH; Event: QEventH): Boolean; cdecl;
 var
   AObject: TQtObject;
-  W: TQtMainWindow;
+  W: TQtWidget;
   LCLEvent: QLCLMessageEventH;
   ASequence: QKeySequenceH;
   AKey: WideString;
@@ -809,8 +809,9 @@ begin
         // eat next appdeactivate & appactivate since we are changing form
         // flags !
         if (StayOnTopList <> nil) then
-          W := TQtMainWindow(HWNDFromWidgetH(QApplication_activeWindow()))
-        else
+        begin
+          W := TQtWidget(GetActiveWindow);
+        end else
           W := nil;
         Application.IntfAppActivate;
         QtRestoreStayOnTop;
diff --git a/lcl/interfaces/qt/qtwinapi.inc b/lcl/interfaces/qt/qtwinapi.inc
index 7fd0c28b33..7d8e338dc6 100644
--- a/lcl/interfaces/qt/qtwinapi.inc
+++ b/lcl/interfaces/qt/qtwinapi.inc
@@ -2498,12 +2498,17 @@ var
 begin
   Result := 0;
   Widget := QApplication_activeWindow;
-  if Widget <> nil then
+  {return modal if activeWindow is nil issue #33409}
+  if Widget = nil then
+    Widget := QApplication_activeModalWidget;
+  if Widget = nil then
+    Widget := QApplication_activePopupWidget;
+  if Assigned(Widget) then
   begin
     W := QtObjectFromWidgetH(Widget);
-    if W <> nil then
+    if Assigned(W) and IsValidHandle(HWND(W)) then
     begin
-      if TQtMainWindow(W).MDIAreaHandle <> nil then
+      if (TQtWidget(W) is TQtMainWindow) and (TQtMainWindow(W).MDIAreaHandle <> nil) then
       begin
         Area := QMdiAreaH(TQtMainWindow(W).MDIAreaHandle.Widget);
         SubW := QtObjectFromWidgetH(QMdiArea_activeSubWindow(Area));
diff --git a/lcl/interfaces/qt5/qtobject.inc b/lcl/interfaces/qt5/qtobject.inc
index 2381ec23f7..f611147136 100644
--- a/lcl/interfaces/qt5/qtobject.inc
+++ b/lcl/interfaces/qt5/qtobject.inc
@@ -574,7 +574,7 @@ end;
 function TQtWidgetSet.EventFilter(Sender: QObjectH; Event: QEventH): Boolean; cdecl;
 var
   AObject: TQtObject;
-  W: TQtMainWindow;
+  W: TQtWidget;
   LCLEvent: QLCLMessageEventH;
   ASequence: QKeySequenceH;
   AKey: WideString;
@@ -764,7 +764,7 @@ begin
         // eat next appdeactivate & appactivate since we are changing form
         // flags !
         if (StayOnTopList <> nil) then
-          W := TQtMainWindow(HWNDFromWidgetH(QApplication_activeWindow()))
+          W := TQtWidget(GetActiveWindow)
         else
           W := nil;
         Application.IntfAppActivate;
diff --git a/lcl/interfaces/qt5/qtwinapi.inc b/lcl/interfaces/qt5/qtwinapi.inc
index 1a00b89dc0..ab99165e36 100644
--- a/lcl/interfaces/qt5/qtwinapi.inc
+++ b/lcl/interfaces/qt5/qtwinapi.inc
@@ -2445,12 +2445,17 @@ var
 begin
   Result := 0;
   Widget := QApplication_activeWindow;
+  {return modal if activeWindow is nil issue #33409}
+  if Widget = nil then
+    Widget := QApplication_activeModalWidget;
+  if Widget = nil then
+    Widget := QApplication_activePopupWidget;
   if Widget <> nil then
   begin
     W := QtObjectFromWidgetH(Widget);
-    if W <> nil then
+    if Assigned(W) and IsValidHandle(HWND(W)) then
     begin
-      if TQtMainWindow(W).MDIAreaHandle <> nil then
+      if (TQtWidget(W) is TQtMainWindow) and Assigned(TQtMainWindow(W).MDIAreaHandle) then
       begin
         Area := QMdiAreaH(TQtMainWindow(W).MDIAreaHandle.Widget);
         SubW := QtObjectFromWidgetH(QMdiArea_activeSubWindow(Area));
@@ -6007,6 +6012,8 @@ var
   W: QWidgetH;
 begin
   {$IFDEF HASX11}
+  {$note this should return current system active window, not
+    application one, if our app isn''t active.}
   if WindowManagerName = 'metacity' then
     W := X11GetActivewindow
   else