I have found that when I want to have things sized perfectly in a client that I also need to process the WM_SIZE message to maintain proper sizing of the child.

If you want the derived class to have its own, separate copy of the static member, you have to declare it in the derived class. Then, you also have to implement Dynamic() in the derived class so it refers to the derived class' static member and not the base class' static member.

This is exactly what I have now.. and doesn't work. Are you sure this is supposed to work?

An alternative to providing a new wndproc for the button, the button control sends a BN_CLICKED message through a WM_COMMAND to the parent window when the button is click. You'll be able to listen out for that. I find that easier (depending on the circumstances) than providing a new wndproc for the button. Phil