Fix a regression from 3bea06b8. This partly reverts 6a2e414d, which introduced this bug initially. With 3bea06b8, it becomes much more likely that indices (-1, -1, -1, -1) got sent to window managers. This can happen, for example, a game with a 1920x1080 window changes the display resolution to 3840x2160, then changes the window size to 3840x2160. After the resolution change and before the window size change, xinerama_get_fullscreen_monitors() will return monitor indices (-1, -1, -1, -1) because 1920x1080 is not fullscreen. While sending a _NET_WM_FULLSCREEN_MONITORS client message with fullscreen monitor indices (-1, -1, -1, -1) clears the _NET_WM_FULLSCREEN_MONITORS property for a window on KWin, it can also make the window to disappear and lose focus. See KWin X11Window::fullscreenMonitorsArea()[1] and X11Window::updateFullscreenMonitors()[2]. Note that QRect is constructed with an empty rect at the beginning of X11Window::fullscreenMonitorsArea(). So fullscreen monitor indices (-1, -1, -1, -1) will produce an empty rect for moveResize() in X11Window::updateFullscreenMonitors() and cause the window to disappear. While indices (-1, 0, 0, 0) might work, I think it's better not to change _NET_WM_FULLSCREEN_MONITORS when the window is not fullscreen because removing the property is not part of any standard. [1]: https://invent.kde.org/plasma/kwin-x11/-/blob/v6.5.4/src/x11window.cpp?ref_t... [2]: https://invent.kde.org/plasma/kwin-x11/-/blob/v6.5.4/src/x11window.cpp?ref_t... Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=59180 -- https://gitlab.winehq.org/wine/wine/-/merge_requests/9841