Quote Originally Posted by readsuhang View Post
.... After I create the tree control in the FrameWndProc ON_CREATE, ...
Are using MFC?
If YES - then why are you using FrameWndProc ?
If NOT - then why do you mention ON_CREATE?

If you could use MFC then you life would be much easier, because AppWizard would make the most work for you creating the "frame" of the MDI app with the "Explorer" style...