fix initial state MDICloseButton after create main form

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@2546 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/rx/rxmdi.pas

@@ -116,6 +116,7 @@ type
     procedure SetTaskPanel(AValue: TRxMDITasks);
   protected
     procedure Notification(AComponent: TComponent; Operation: TOperation); override;
+    procedure Loaded; override;
   public
     constructor Create(TheOwner: TComponent); override;
     procedure ShowWindow(F:TForm);
@@ -278,6 +279,12 @@ begin
     FTaskPanel:=nil;
 end;
 
+procedure TRxMDIPanel.Loaded;
+begin
+  inherited Loaded;
+  CurrentChildWindow:=nil;
+end;
+
 constructor TRxMDIPanel.Create(TheOwner: TComponent);
 begin
   inherited Create(TheOwner);