36. My app leaves a phantom gray button on the taskbar when it exits. Why?
You get this problem when you change the window styles that affect the visibility
of a window in the taskbar, you naughty little tinker....
For example, if you change your windows extended style to include WS_EX_TOOLWINDOW style
(a common trick to prevent a window appearing in the taskbar) and then fail to reset the extended style before closing the window, the taskbar shows a
phantom gray button, which vanishes when clicked.
Solutions ?
- Reset the style bits of the window before
closing your app, or
-
Call ShowWindow with SW_HIDE for the application's main window while processing WM_CLOSE or WM_DESTROY.
