diff --git a/components/ideintf/componenttreeview.pas b/components/ideintf/componenttreeview.pas
index dd933aea96..6a9fca9abb 100644
--- a/components/ideintf/componenttreeview.pas
+++ b/components/ideintf/componenttreeview.pas
@@ -747,7 +747,6 @@ begin
   FPersToChange := APersistent;
   FZOrderDelete := AZOrder;
   BuildComponentNodes(False);
-  Assert(FPersToChange=nil, 'TComponentTreeView.ChangeCompZOrder: FPersToChange is assigned.');
 end;
 
 procedure TComponentTreeView.DeleteComponentNode(APersistent: TPersistent);
@@ -755,7 +754,6 @@ begin
   FPersToChange := APersistent;
   FZOrderDelete := zoDelete;
   BuildComponentNodes(False);
-  Assert(FPersToChange=nil, 'TComponentTreeView.DeleteComponentNode: FPersToChange is assigned.');
 end;
 
 procedure TComponentTreeView.UpdateCompNode(ANode: TTreeNode);
diff --git a/designer/designer.pp b/designer/designer.pp
index bbd4a74000..4bd74ad4aa 100644
--- a/designer/designer.pp
+++ b/designer/designer.pp
@@ -37,8 +37,9 @@ interface
 {off $DEFINE VerboseDesignerSelect}
 
 uses
-  // RTL + FCL + LCL
-  Types, Classes, Math, SysUtils, variants, TypInfo,
+  // RTL + FCL
+  Types, Classes, Math, SysUtils, Variants, TypInfo,
+  // LCL
   LCLProc, LCLType, LResources, LCLIntf, LMessages, InterfaceBase,
   Forms, Controls, GraphType, Graphics, Dialogs, ExtCtrls, Menus, ClipBrd,
   // LazUtils
@@ -1631,10 +1632,21 @@ begin
 end;
 
 procedure TDesigner.NotifyComponentAdded(AComponent: TComponent);
+var
+  i: Integer;
+  SubContrl: TControl;
 begin
   try
     if AComponent.Name='' then
       AComponent.Name:=UniqueName(AComponent.ClassName);
+    // Iterating Controls is needed at least for Side1 and Side2 of TPairSplitter.
+    if AComponent is TWinControl then
+      for i:=0 to TWinControl(AComponent).ControlCount-1 do
+      begin
+        SubContrl:=TWinControl(AComponent).Controls[i];
+        if SubContrl.Name='' then
+          SubContrl.Name:=UniqueName(SubContrl.ClassName);
+      end;
     GlobalDesignHook.PersistentAdded(AComponent,false);
   except
     on E: Exception do
diff --git a/ide/customformeditor.pp b/ide/customformeditor.pp
index 654f51a9b2..7bc8cd22dd 100644
--- a/ide/customformeditor.pp
+++ b/ide/customformeditor.pp
@@ -1363,7 +1363,7 @@ begin
           AParent:=AParent.Parent;
         end;
       end;
-      DebugLn('Parent is '''+dbgsName(AParent)+'''');
+      //DebugLn('TCustomFormEditor.CreateComponent: Parent is '''+dbgsName(AParent)+'''');
     end else begin
       // create a toplevel component
       // -> a form or a datamodule or a custom component