diff --git a/lcl/controls.pp b/lcl/controls.pp
index 2f9f0dc594..7c2d965448 100644
--- a/lcl/controls.pp
+++ b/lcl/controls.pp
@@ -418,6 +418,12 @@ type
     procedure AdjustDockRect(ARect: TRect); virtual;
     function GetDragCursor(Accepted: Boolean; X, Y: Integer): TCursor; override;
     procedure EndDrag(Target: TObject; X, Y: Integer); override;
+
+    // dock image drawing
+    procedure InitDock(APosition: TPoint); virtual;
+    procedure ShowDockImage; virtual;
+    procedure HideDockImage; virtual;
+    procedure MoveDockImage; virtual;
   public
     property DockOffset: TPoint read FDockOffset write FDockOffset;
     property DockRect: TRect read FDockRect write FDockRect;
diff --git a/lcl/include/dragmanager.inc b/lcl/include/dragmanager.inc
index 08e56ce343..911aec4b8d 100644
--- a/lcl/include/dragmanager.inc
+++ b/lcl/include/dragmanager.inc
@@ -8,7 +8,7 @@
  *                                                                           *
  *  This file is part of the Lazarus Component Library (LCL)                 *
  *                                                                           *
- *  See the file COPYING.modifiedLGPL.txt, included in this distribution,        *
+ *  See the file COPYING.modifiedLGPL.txt, included in this distribution,    *
  *  for details about the copyright.                                         *
  *                                                                           *
  *  This program is distributed in the hope that it will be useful,          *
@@ -59,7 +59,6 @@ type
   TDockPerformer = class(TDragDockCommon)
   private
     FDockObject: TDragDockObject;
-    procedure DefaultDockImage(AOldRect, ANewRect: TRect; AOperation: TDockImageOperation);
   protected
     function Dragging(AControl: TControl): boolean; override;
     procedure DragStarted(APosition: TPoint); override;
@@ -264,27 +263,15 @@ end;
 constructor TDockPerformer.Create(AManager: TDragManagerDefault; AControl: TControl);
 //Start a drag operation, if not already running
 var
-  p, cp: TPoint;
+  APoint: TPoint;
 begin
   inherited Create(AManager, AControl);
   AControl.DoStartDock(FDockObject);
   if FDockObject = nil then
     FDockObject := TDragDockObject.AutoCreate(AControl);
 
-  // we should handle somehow difference between
-  // Control.BoundsRect.LeftTop and CursorPos
-  
-  GetCursorPos(p);
-  FDockObject.DragPos := p;
-  // mouse click offset from control TopLeft in screen coordinates
-  cp := AControl.BoundsRect.TopLeft;
-  if AControl.Parent <> nil then
-    cp := AControl.Parent.ClientToScreen(cp);
-  FDockObject.DockOffset := Point(p.x - cp.x, p.y - cp.y);
-  AControl.CalculateDockSizes;
-  FDockObject.DockRect := Rect(p.x, p.y, p.x + AControl.Width, p.y + AControl.Height);
-  FDockObject.EraseDockRect := Rect(MaxInt, 0, MaxInt, 0);
-  
+  GetCursorPos(APoint);
+  FDockObject.InitDock(APoint);
   // we are tracking capture change to stop drag/dock is happen
   SetCaptureControl(AControl);
 end;
@@ -301,15 +288,14 @@ begin
 end;
 
 procedure TDockPerformer.DragStarted(APosition: TPoint);
-//Imput device has moved beyond tresholt (or immediate docking)
+// Input device has moved beyond threshold (or immediate docking)
 begin
   if FDockObject = nil then
     Exit;
   FDragImageList := FDockObject.GetDragImages;
   if FDragImageList <> nil then
     FDragImageList.BeginDrag(0, APosition.X, APosition.Y);
-  DefaultDockImage(FDockObject.EraseDockRect, FDockObject.DockRect, disShow);
-  FDockObject.EraseDockRect := FDockObject.DockRect;
+  FDockObject.ShowDockImage;
 end;
 
 procedure TDockPerformer.DragMove(APosition: TPoint);
@@ -468,12 +454,7 @@ begin
         DropAlign := DropOnControl.GetDockEdge(DropOnControl.ScreenToClient(APosition));
     end;
 
-    //Draw the form outlines when the position has changed
-    if not CompareMem(@DockRect, @EraseDockRect, SizeOf(TRect)) then
-    begin
-      DefaultDockImage(FDockObject.EraseDockRect, FDockObject.DockRect, disMove);
-      EraseDockRect := DockRect;
-    end;
+    MoveDockImage;
   end;
 end;
 
@@ -491,7 +472,7 @@ begin
     FDockObject := nil;
     SetCaptureControl(nil);
 
-    DefaultDockImage(ADockObjectCopy.EraseDockRect, ADockObjectCopy.DockRect, disHide);
+    ADockObjectCopy.HideDockImage;
     ADockObjectCopy.Floating := ADockObjectCopy.DragTarget = nil;
 
     Accepted := ADockObjectCopy.DragTarget <> nil;
@@ -547,11 +528,6 @@ begin
 end;
 
 
-procedure TDockPerformer.DefaultDockImage(AOldRect, ANewRect: TRect; AOperation: TDockImageOperation);
-begin
-  WidgetSet.DrawDefaultDockImage(AOldRect, ANewRect, AOperation);
-end;
-
 { TDragManagerDefault }
 
 destructor TDragManagerDefault.Destroy;
diff --git a/lcl/include/dragobject.inc b/lcl/include/dragobject.inc
index db32de8f79..c84fad43b1 100644
--- a/lcl/include/dragobject.inc
+++ b/lcl/include/dragobject.inc
@@ -112,6 +112,49 @@ begin
     FControl.DoEndDock(Target, X, Y);
 end;
 
+procedure TDragDockObject.InitDock(APosition: TPoint);
+begin
+  // Determine hotspot scale for adjusting the undocked rectangle.
+  // Since the undocked extent of the control doesn't change, we fix the hotspot offset.
+  // Usage: OffsetRect(DockRect, FDockOffset);
+
+  DragPos := APosition; //should have been done before
+  Control.CalculateDockSizes;
+  // mouse click offset from control TopLeft in screen coordinates
+  FDockRect.TopLeft := Control.ClientToScreen(Point(0, 0));
+  if Control.Width > 0 then
+    FDockOffset.x := Round((APosition.x - FDockRect.Left) / Control.Width * Control.UndockWidth)
+  else
+    FDockOffset.X := 0;
+  if Control.Height > 0 then
+    FDockOffset.Y := Round((APosition.y - FDockRect.Top) / Control.Height * Control.UndockHeight)
+  else
+    FDockOffset.Y := 0;
+  FEraseDockRect := Rect(MaxInt, 0, MaxInt, 0);
+end;
+
+procedure TDragDockObject.ShowDockImage;
+begin
+  WidgetSet.DrawDefaultDockImage(EraseDockRect, DockRect, disShow);
+  EraseDockRect := DockRect;
+end;
+
+procedure TDragDockObject.HideDockImage;
+begin
+  WidgetSet.DrawDefaultDockImage(EraseDockRect, DockRect, disHide);
+  FEraseDockRect := Rect(MaxInt, 0, MaxInt, 0);
+end;
+
+procedure TDragDockObject.MoveDockImage;
+begin
+  //Draw the form outlines when the position has changed
+  if not CompareMem(@DockRect, @EraseDockRect, SizeOf(TRect)) then
+  begin
+    WidgetSet.DrawDefaultDockImage(EraseDockRect, DockRect, disMove);
+    EraseDockRect := DockRect;
+  end;
+end;
+
 { TDragDockObjectEx }
 
 constructor TDragDockObjectEx.Create(AControl: TControl);