internal void HidePlaceholder()
 {
     if (placeholderWindow != null)
     {
         placeholderWindow.Destroy();
         placeholderWindow = null;
     }
     if (padTitleWindow != null)
     {
         padTitleWindow.Destroy();
         padTitleWindow = null;
     }
 }
 internal void ShowPlaceholder(DockItem draggedItem)
 {
     padTitleWindow = new PadTitleWindow(frame, draggedItem);
      placeholderWindow = new PlaceholderWindow(frame);
 }
 internal void ShowPlaceholder(DockItem draggedItem)
 {
     padTitleWindow    = new PadTitleWindow(frame, draggedItem);
     placeholderWindow = new PlaceholderWindow(frame);
 }
 internal void HidePlaceholder()
 {
     if (placeholderWindow != null)
      {
     placeholderWindow.Destroy();
     placeholderWindow = null;
      }
      if (padTitleWindow != null)
      {
     padTitleWindow.Destroy();
     padTitleWindow = null;
      }
 }