I've tested this on weston and on my own toy WM, so I guess this is a bug in libweston. When I open chrome or chromium, they are not decorated by the WM(which is fine). However, their "custom" buttons for maximization don't work. In other Xwayland views, the maximize button on the frames drawn by weston are working fine. So my guess is that the maximize request from Xwayland isn't implemented in XWM.
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