How to change the content in the same toolwindow dynamically

Hi All:

Can anybody help me figure out how to dynamically change the toolwindow content?

I have created a single instance toolwindow

"public class MyToolWindow : ToolWindowPane, IVsWindowFrameNotify3". I have set the a user control to the "Content" in the construction. It works properly.

But now the requirement is:

When user clicks the button A, the content in this toolwindow will be shown the button A related information.  Don't close this toolwindow.

When user clicks the button B, the content in this toolwindow will be shown the button B related information.

Maybe it is an easy question, but I have tried several solution. It doesn't work.

Could anybody help me figure out how to change the content in the toolwindow.

Thanks in advance.