When logging into Xfce, on any distro, with compositing turned on, usually in the top left corner of the screen there is a small weird gray box that goes away after a while. This is a very trivial thing, but it is a bug. This happens regardless of X.org version or video driver. Video driver used was xf86-video-intel 2.18 and X.org 1.12.0. Graphics chipset is the G41.
A few pixels tiny square window of the same color as gtk apps? That's most likely an app mapping a window, not a bug in xfwm4.
Changing the GTK theme doesn't seem to affect it.
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