Element already has a logical parent. It must be detached from the old parent before it is attached

Hi,

How to remove exception like Element already has a logical parent. It must be detached from the old parent before it is attached to a new one.

For Example

ToolWindowContainer con = newToolWindowContainer();

con.Items.Add(toolWindow);

BaseDocksite.AutoHideLeftContainers.Add(con);

toolwindow that i want to add in the con(ToolwindowContainer) is attached with the Logical parent that  is its container.

If i reterieve the container using

ToolWindowContainer ablContainer = toolWindow.Parent asToolWindowContainer;

and then close this container using

ablContainer.Close();

con.Items.Add(toolWindow);

BaseDocksite.AutoHideLeftContainers.Add(con);

its working fine.

But I  don't want to close this container attached with the toolwindow.

So how to solve this problem without closing  this container attached with the toolwindow.