How to remove customized ToolWindowPane from VS isolated shell at runtime

Hi all, 

   I have registered  to a customized ToolWindowPane from isolated shell used by :

     ToolWindowPane window =
         Package. FindToolWindow(
         typeof(xxx), 0, true);

At runtime , i also want to remove it from isolated shell,  so that after remove it ,  i can renew a instance when i called    ToolWindowPane window =Package. FindToolWindow(typeof(xxx), 0, true) on next time.