diff --git a/lcl/include/intfbasewinapi.inc b/lcl/include/intfbasewinapi.inc
index 9287b7d90c..e403325cd5 100644
--- a/lcl/include/intfbasewinapi.inc
+++ b/lcl/include/intfbasewinapi.inc
@@ -2019,6 +2019,11 @@ begin
   Result := True;
 end;
 
+function TWidgetSet.SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean;
+begin
+  Result := False;
+end;
+
 function TWidgetSet.SetROP2(DC: HDC; Mode: Integer): Integer;
 begin
   Result := 0;
diff --git a/lcl/include/winapi.inc b/lcl/include/winapi.inc
index 44fb533e6f..cc5874d9bb 100644
--- a/lcl/include/winapi.inc
+++ b/lcl/include/winapi.inc
@@ -886,6 +886,11 @@ begin
   Result := WidgetSet.SetProp(Handle,Str,Data);
 end;
 
+function SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean;
+begin
+  Result := WidgetSet.SetRectRgn(aRGN, X1, Y1, X2, Y2);
+end;
+
 function SetROP2(DC: HDC; Mode: Integer): Integer;
 begin
   Result := WidgetSet.SetRop2(Dc, Mode);
diff --git a/lcl/include/winapih.inc b/lcl/include/winapih.inc
index 880ed51586..fd44b1aad8 100644
--- a/lcl/include/winapih.inc
+++ b/lcl/include/winapih.inc
@@ -250,6 +250,7 @@ function SetMenu(AWindowHandle: HWND; AMenuHandle: HMENU): Boolean; {$IFDEF IF_B
 function SetParent(hWndChild: HWND; hWndParent: HWND): HWND; {$IFDEF IF_BASE_MEMBER}virtual;{$ENDIF}
 function SetProp(Handle: hwnd; Str : PChar; Data : Pointer) : Boolean; {$IFDEF IF_BASE_MEMBER}virtual;{$ENDIF}
 //function SetRect --> independent
+function SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean; {$IFDEF IF_BASE_MEMBER}virtual;{$ENDIF}
 //function SetRectEmpty --> independent
 function SetROP2(DC: HDC; Mode: Integer): Integer; {$IFDEF IF_BASE_MEMBER}virtual;{$ENDIF}
 function SetScrollInfo(Handle: HWND; SBStyle: Integer; ScrollInfo: TScrollInfo; Redraw : Boolean): Integer; {$IFDEF IF_BASE_MEMBER}virtual;{$ENDIF}
diff --git a/lcl/interfaces/gtk/gtkwinapi.inc b/lcl/interfaces/gtk/gtkwinapi.inc
index d858cc95a1..3e39192588 100644
--- a/lcl/interfaces/gtk/gtkwinapi.inc
+++ b/lcl/interfaces/gtk/gtkwinapi.inc
@@ -9064,6 +9064,36 @@ begin
   Result:=true;
 end;
 
+{------------------------------------------------------------------------------
+  Method: SetRectRgn
+  Params:  aRGN: HRGN; X1, Y1, X2, Y2 : Integer
+  Returns: True if the function succeeds
+
+  Converts a region into a rectangular region with the specified coordinates.
+ ------------------------------------------------------------------------------}
+function TGtkWidgetSet.SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean;
+
+  procedure Swap(var A, B: Integer);
+  var
+    Tmp: Integer;
+  begin
+    Tmp := A;
+    A := B;
+    B := Tmp;
+  end;
+
+var
+  AGdiObject: PGdiObject absolute aRGN;
+begin
+  Result := IsValidGDIObject(aRGN);
+  if Result then begin
+    if (X1 > X2) then swap(X1, X2);
+    if (Y1 > Y2) then swap(Y1, Y2);
+    AGdiObject^.GDIRegionObject := CreateRectGDKRegion(Rect(X1,Y1,X2,Y2));
+    Result := True;
+  end;
+end;
+
 {------------------------------------------------------------------------------
   function TGtkWidgetSet.SetROPMode(Handle: hwnd; Str : PChar;
                               Data : Pointer) : Boolean;
diff --git a/lcl/interfaces/gtk/gtkwinapih.inc b/lcl/interfaces/gtk/gtkwinapih.inc
index 4bbf530839..0a869c6fb9 100644
--- a/lcl/interfaces/gtk/gtkwinapih.inc
+++ b/lcl/interfaces/gtk/gtkwinapih.inc
@@ -201,6 +201,7 @@ function SetForegroundWindow(hWnd: HWND): boolean; override;
 function SetMapMode(DC: HDC; fnMapMode : Integer): Integer; override;
 function SetParent(hWndChild: HWND; hWndParent: HWND): HWND; override;
 function SetProp(Handle: hwnd; Str : PChar; Data : Pointer) : Boolean; override;
+function SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean; override;
 function SetROP2(DC: HDC; Mode: Integer): Integer; override;
 function SetScrollInfo(Handle : HWND; SBStyle : Integer; ScrollInfo: TScrollInfo; bRedraw : Boolean): Integer; override;
 function SetSysColors(cElements: Integer; const lpaElements; const lpaRgbValues): Boolean; override;
diff --git a/lcl/interfaces/gtk2/gtk2winapi.inc b/lcl/interfaces/gtk2/gtk2winapi.inc
index 9c43e3d9bd..f48f15d107 100644
--- a/lcl/interfaces/gtk2/gtk2winapi.inc
+++ b/lcl/interfaces/gtk2/gtk2winapi.inc
@@ -8467,6 +8467,36 @@ begin
   Result:=true;
 end;
 
+{------------------------------------------------------------------------------
+  Method: SetRectRgn
+  Params:  aRGN: HRGN; X1, Y1, X2, Y2 : Integer
+  Returns: True if the function succeeds
+
+  Converts a region into a rectangular region with the specified coordinates.
+ ------------------------------------------------------------------------------}
+function TGtk2WidgetSet.SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean;
+
+  procedure Swap(var A, B: Integer);
+  var
+    Tmp: Integer;
+  begin
+    Tmp := A;
+    A := B;
+    B := Tmp;
+  end;
+
+var
+  AGdiObject: PGdiObject absolute aRGN;
+begin
+  Result := IsValidGDIObject(aRGN);
+  if Result then begin
+    if (X1 > X2) then swap(X1, X2);
+    if (Y1 > Y2) then swap(Y1, Y2);
+    AGdiObject^.GDIRegionObject := CreateRectGDKRegion(Rect(X1,Y1,X2,Y2));
+    Result := True;
+  end;
+end;
+
 {------------------------------------------------------------------------------
   function TGtk2WidgetSet.SetROPMode(Handle: hwnd; Str : PChar;
                               Data : Pointer) : Boolean;
diff --git a/lcl/interfaces/gtk2/gtk2winapih.inc b/lcl/interfaces/gtk2/gtk2winapih.inc
index 6d29f44a23..dd1d2f9957 100644
--- a/lcl/interfaces/gtk2/gtk2winapih.inc
+++ b/lcl/interfaces/gtk2/gtk2winapih.inc
@@ -214,6 +214,7 @@ function SetForegroundWindow(hWnd: HWND): boolean; override;
 function SetMapMode(DC: HDC; fnMapMode : Integer): Integer; override;
 function SetParent(hWndChild: HWND; hWndParent: HWND): HWND; override;
 function SetProp(Handle: hwnd; Str : PChar; Data : Pointer) : Boolean; override;
+function SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean; override;
 function SetROP2(DC: HDC; Mode: Integer): Integer; override;
 function SetScrollInfo(Handle : HWND; SBStyle : Integer; ScrollInfo: TScrollInfo; bRedraw : Boolean): Integer; override;
 function SetSysColors(cElements: Integer; const lpaElements; const lpaRgbValues): Boolean; override;
diff --git a/lcl/interfaces/win32/win32winapi.inc b/lcl/interfaces/win32/win32winapi.inc
index f189bf26d4..5b7a4c2358 100644
--- a/lcl/interfaces/win32/win32winapi.inc
+++ b/lcl/interfaces/win32/win32winapi.inc
@@ -3192,6 +3192,19 @@ begin
   Result := Boolean(Windows.SetProp(Handle, Str, Windows.HANDLE(Data)));
 end;
 
+{------------------------------------------------------------------------------
+  Method: SetRectRgn
+  Params:  aRGN: HRGN; X1, Y1, X2, Y2 : Integer
+  Returns: True if the function succeeds
+
+  Converts a region into a rectangular region with the specified coordinates.
+
+ ------------------------------------------------------------------------------}
+function TWin32WidgetSet.SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean;
+begin
+  Result := Boolean(Windows.SetRectRgn(aRGN, X1, Y1, X2, Y2));
+end;
+
 {------------------------------------------------------------------------------
   Method:  SetROP2
   Params:  DC			- Device Context
diff --git a/lcl/interfaces/win32/win32winapih.inc b/lcl/interfaces/win32/win32winapih.inc
index 0f956506d2..dc3fd96ce1 100644
--- a/lcl/interfaces/win32/win32winapih.inc
+++ b/lcl/interfaces/win32/win32winapih.inc
@@ -213,6 +213,7 @@ function SetMapMode(DC: HDC; fnMapMode : Integer): Integer; override;
 function SetMenu(AWindowHandle: HWND; AMenuHandle: HMENU): Boolean; override;
 function SetParent(hWndChild: HWND; hWndParent: HWND): HWND; override;
 function SetProp(Handle: hwnd; Str: PChar; Data: Pointer): Boolean; override;
+function SetRectRgn(aRGN: HRGN; X1, Y1, X2, Y2 : Integer): Boolean; override;
 function SetROP2(DC: HDC; Mode: Integer): Integer; override;
 function SetScrollInfo(Handle: HWND; SBStyle: Integer; ScrollInfo: TScrollInfo; BRedraw: Boolean): Integer; override;
 function SetStretchBltMode(DC: HDC; StretchMode: Integer): Integer; override;