Is there any reason why you shouldn't use CreateWindow in a DLL?
I've got an application that calls a function in a custom DLL from its
wndproc. In the DLL, I am creating a window using CreateWindow with
WS_POPUPWINDOW | WS_CAPTION | WS_CHILD, and displaying it modally (i.e.
executing a message pump in the DLL's function).
This works almost fine, i.e. the window displays and closes again and is
like a child popup window should be, but the window does 'jump around' a
bit, i.e. when you try to select the background (main app's) window, then
click on the caption of the child window, it does a little hop to another
area of the screen. Not far, but it's definitely more than the negligible
amount of dragging associated with the clicking. The DLL only registers its
wndclassex on the first call to it, after that, it just uses the same one. I
am also calling DestroyWindow on the child window before exiting the DLL
function.
I did rethink about the design of the app and decided that using
CreateDialog with a dialog resource might be better. (Also to that, is there
any reference on the commands used in the .rc file for the dialog resource?)
But I'm hesitant to, for fear the same thing may happen if I don't know
what's causing it, whereas if I can isolate the problem I can make sure it's
not due to the fact that it's in a DLL.

Thanks