From 26266caedc37b1b7970f428c4581c0ba3405c826 Mon Sep 17 00:00:00 2001
From: zeljan1 <zeljko@holobit.hr>
Date: Wed, 14 May 2025 13:17:17 +0200
Subject: [PATCH] Qt5,Qt6: fixed painting in designer when using docked form
 designer. issue #41640

---
 lcl/interfaces/qt5/qtint.pp      |  1 +
 lcl/interfaces/qt5/qtwidgets.pas | 14 ++++++++++++++
 lcl/interfaces/qt6/qtint.pp      |  1 +
 lcl/interfaces/qt6/qtwidgets.pas | 14 ++++++++++++++
 4 files changed, 30 insertions(+)

diff --git a/lcl/interfaces/qt5/qtint.pp b/lcl/interfaces/qt5/qtint.pp
index f7f6dc88c7..7cb77c4a73 100644
--- a/lcl/interfaces/qt5/qtint.pp
+++ b/lcl/interfaces/qt5/qtint.pp
@@ -329,6 +329,7 @@ const
    // combobox OnCloseUp should be in order OnChange->OnSelect->OnCloseUp
    LCLQt_ComboBoxCloseUp = QEventType(Ord(QEventUser) + $1012);
    LCLQt_DestroyWidget = QEventType(Ord(QEventUser) + $1013);
+   LCLQt_DesignerUpdate = QEventType(Ord(QEventUser) + $1014);
 
 
    QtTextSingleLine            = $0100;
diff --git a/lcl/interfaces/qt5/qtwidgets.pas b/lcl/interfaces/qt5/qtwidgets.pas
index 31bfe435b3..ddf7b65346 100644
--- a/lcl/interfaces/qt5/qtwidgets.pas
+++ b/lcl/interfaces/qt5/qtwidgets.pas
@@ -20307,6 +20307,7 @@ var
   YStep, XStep: integer;
   B: Boolean;
   Bar: TQtScrollBar;
+  ALCLEvent: QLCLMessageEventH;
 
   function FindScrolledParent(AControl: TWinControl): TWinControl;
   begin
@@ -20512,9 +20513,22 @@ begin
       end;
       QEventPaint:
       begin
+        if Assigned(LCLObject) and (LCLObject.Parent <> nil) and Assigned(FMenuBar) and
+          FMenuBar.FVisible then
+        begin
+          QPaintEvent_rect(QPaintEventH(Event), @R);
+          if (R.Width < QWidget_width(FDesignControl)) or
+            (R.Height < QWidget_height(FDesignControl)) then
+          begin
+            ALCLEvent := QLCLMessageEvent_create(LCLQt_DesignerUpdate, 0, 0, 0, 0);
+            QCoreApplication_postEvent(FDesignControl, ALCLEvent, Ord(QtHighEventPriority));
+            exit(True);
+          end;
+        end;
         SlotDesignControlPaint(Sender, Event);
         Result := True;
       end;
+      LCLQt_DesignerUpdate: QWidget_update(FDesignControl);
       QEventContextMenu: SlotContextMenu(Sender, Event);
     end;
   finally
diff --git a/lcl/interfaces/qt6/qtint.pp b/lcl/interfaces/qt6/qtint.pp
index 10bb02270e..77726c3275 100644
--- a/lcl/interfaces/qt6/qtint.pp
+++ b/lcl/interfaces/qt6/qtint.pp
@@ -334,6 +334,7 @@ const
    // combobox OnCloseUp should be in order OnChange->OnSelect->OnCloseUp
    LCLQt_ComboBoxCloseUp = QEventType(Ord(QEventUser) + $1012);
    LCLQt_DestroyWidget = QEventType(Ord(QEventUser) + $1013);
+   LCLQt_DesignerUpdate = QEventType(Ord(QEventUser) + $1014);
 
 
    QtTextSingleLine            = $0100;
diff --git a/lcl/interfaces/qt6/qtwidgets.pas b/lcl/interfaces/qt6/qtwidgets.pas
index c4fa9ecad5..e08aa99e01 100644
--- a/lcl/interfaces/qt6/qtwidgets.pas
+++ b/lcl/interfaces/qt6/qtwidgets.pas
@@ -20232,6 +20232,7 @@ var
   YStep, XStep: integer;
   B: Boolean;
   Bar: TQtScrollBar;
+  ALCLEvent: QLCLMessageEventH;
 
   function FindScrolledParent(AControl: TWinControl): TWinControl;
   begin
@@ -20437,9 +20438,22 @@ begin
       end;
       QEventPaint:
       begin
+        if Assigned(LCLObject) and (LCLObject.Parent <> nil) and Assigned(FMenuBar) and
+          FMenuBar.FVisible then
+        begin
+          QPaintEvent_rect(QPaintEventH(Event), @R);
+          if (R.Width < QWidget_width(FDesignControl)) or
+            (R.Height < QWidget_height(FDesignControl)) then
+          begin
+            ALCLEvent := QLCLMessageEvent_create(LCLQt_DesignerUpdate, 0, 0, 0, 0);
+            QCoreApplication_postEvent(FDesignControl, ALCLEvent, Ord(QtHighEventPriority));
+            exit(True);
+          end;
+        end;
         SlotDesignControlPaint(Sender, Event);
         Result := True;
       end;
+      LCLQt_DesignerUpdate: QWidget_update(FDesignControl);
       QEventContextMenu: SlotContextMenu(Sender, Event);
     end;
   finally