"Lei Zhang" thestig@google.com wrote:
On Windows, clicking the close button of a nonactive window generates a WM_MOUSEACTIVATE notification. Applications with custom window procedures can then choose to ignore the close button if they wished to by returning MA_ACTIVATEANDEAT / MA_NOACTIVATEANDEAT.
I'm not sure what you mean by "applications with custom window procedures" because all (even simple ones) window procs in applications are custom, and they are free to handle/ignore any message they like, for instance WM_CLOSE or WM_SYSCOMMAND/SC_CLOSE.
We already send WM_MOUSEACTIVATE message on a take focus X11 event, so I don't see a point in duplicating it. On the other hand if a WM doesn't activate a window when a user clicks on window's caption (where the close button usually placed) then it's a WM bug and we can do nothing to fix it.