Buffer swap from another application.

The xfce4-screenshooter inserts the old area from the Gnome Disk benchmark into the image buffer. Usually shows up with small and medium windows: Terminal, KDiskMark, Thunar, but does not show up with Telegram and Firefox.

Below is an example of a screenshot of Thunar. It inserts an image of the old benchmark on top of the desktop. The size corresponds to the Thunar window.