I now create a CDialog which has a tree control in it and attach to the created pane.
This works well for single document. When I open another document in my application I would like to display the new CDialog relevant to this new document that I created withing the pane.
This works for me.. (In short, the structure is like Visual Studio tabs where we open multiple files and can display its respective information in one of the panes like "Properties" of visual studio.)
When I show/Hide the pane and now switch between the tabs (opened documents), my initial documents dialog handle is null due to which I am facing a crash.

Tried to reproduce:
1. MDI Panes sample, similar operation like click on "Properties"- It should update pane's visibility. I could not support multiple document here based on which we could change the content of the pane (A CDialog instance can be attached to this pane?)

Can you please guide me further to know the reason why would the pane's child window handle (the initial dialog created which is attached as a child to this pane) become null after we hide show the current dialog (2nd document's CDialog instance) in the pane.

I would be glad if anyone can post me a working sample for this. Also wanted to know how is m_layout important in show/hide process.

Regards,
Kalyani