The previous change is not enough, as WM_KILLFOCUS can apparently be
sent to the window losing focus after WM_ACTIVATE has been sent to
the window gaining focus.
Try using WM_SETFOCUS instead, as that has the correct ordering and seems
more logical.
The test "!pWin || !pWin->overrideRedirect" is confusingly written: It's
true if:
(a) pWin is NULL (= X window doesn't exist, shouldn't happen), or
(b) pWin->overrideRedirect is FALSE
i.e. the intended effect is "don't give focus to override redirect windows"
There seem to be some cases where this still isn't quite correct: A
reproduction isn't known, but it seems to be related to minimizing a
maximized Windows window, and having window activation move to a
maximized X window beneath it.
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/736>
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