diff --git a/designer/designer.pp b/designer/designer.pp
index 152bffca07..7c647cc73a 100644
--- a/designer/designer.pp
+++ b/designer/designer.pp
@@ -2991,6 +2991,9 @@ Begin
   // remove all child controls owned by the LookupRoot
   if (APersistent is TWinControl) then begin
     AWinControl:=TWinControl(APersistent);
+    // Component may to auto-create new components during deletion unless informed.
+    // ComponentState does not have csDestroying yet when removing children.
+    AWinControl.DesignerDeleting := True;
     i:=AWinControl.ControlCount-1;
     while (i>=0) do begin
       ChildControl:=AWinControl.Controls[i];
@@ -3005,6 +3008,7 @@ Begin
       end else
         dec(i);
     end;
+    AWinControl.DesignerDeleting := False;
   end;
   // remove component
   {$IFDEF VerboseDesigner}
diff --git a/lcl/controls.pp b/lcl/controls.pp
index ce425de86f..3a0da6a36d 100644
--- a/lcl/controls.pp
+++ b/lcl/controls.pp
@@ -1893,6 +1893,7 @@ type
     FDoubleBuffered: Boolean;
     FDockSite: Boolean;
     FUseDockManager: Boolean;
+    FDesignerDeleting: Boolean;
     procedure AlignControl(AControl: TControl);
     function GetBrush: TBrush;
     function GetControl(const Index: Integer): TControl;
@@ -2120,6 +2121,7 @@ type
     property Showing: Boolean read FShowing; // handle visible
     property UseDockManager: Boolean read FUseDockManager
                                      write SetUseDockManager default False;
+    property DesignerDeleting: Boolean read FDesignerDeleting write FDesignerDeleting;
     property VisibleDockClientCount: Integer read GetVisibleDockClientCount;
   public
     // size, position, bounds
diff --git a/lcl/pairsplitter.pas b/lcl/pairsplitter.pas
index 120bbbaba4..4428d023bc 100644
--- a/lcl/pairsplitter.pas
+++ b/lcl/pairsplitter.pas
@@ -170,19 +170,26 @@ end;
 procedure TPairSplitterSide.SetParent(AParent: TWinControl);
 var
   ASplitter: TCustomPairSplitter;
+  DeletingSplitter: Boolean;
 begin
   CheckNewParent(AParent);
   // remove from side list of old parent
   ASplitter := Splitter;
-  if ASplitter <> nil then
+  if ASplitter <> nil then begin
     ASplitter.RemoveSide(Self);
+    DeletingSplitter := (csDestroying in ASplitter.ComponentState) or DesignerDeleting;
+  end
+  else
+    DeletingSplitter := False;
 
   inherited SetParent(AParent);
 
-  // add to side list of new parent
-  ASplitter:=Splitter;
-  if ASplitter <> nil then
-    ASplitter.AddSide(Self);
+  if not DeletingSplitter then begin
+    // add to side list of new parent
+    ASplitter:=Splitter;
+    if ASplitter <> nil then
+      ASplitter.AddSide(Self);
+  end;
 end;
 
 procedure TPairSplitterSide.WMPaint(var PaintMessage: TLMPaint);
@@ -281,7 +288,7 @@ begin
   i := Low(FSides);
   repeat
     if FSides[i] = ASide then
-    Exit;
+      Exit;
     if FSides[i] =nil then
     begin
       FSides[i] := ASide;
@@ -309,7 +316,8 @@ begin
       FSides[i] := nil;
     end;
   // if the user deletes a side at designtime, autocreate a new one
-  if (csDesigning in ComponentState) then
+  if (ComponentState * [csDesigning,csDestroying] = [csDesigning])
+  and not DesignerDeleting then
     CreateSides;
 end;