Quote Originally Posted by AKE View Post
DialogBox is needed. Solved.
It actually depends on what the purpose was. DialogBox creates modal dialog when CreateDialog creates modeless one.

Code:
HWND hDlg = CreateDialog(...);  // this just creates dialog window
ShowWindow(hDlg, SW_SHOW); // unless WS_VISIBLE was specified at creation
UpdateWindow(hDlg);

// message pump is also needed running on this thread