Comment # 5 on bug 934644 from Jan Engelhardt

I installed kicad-unstable(-20150610-R5730) from the electronics repository. I
run it without specifying a project file, so it starts with a blank slate.

Even after clicking a toolbar icon, resizing the child window produces no
artifacts, unfortunately. IOW, I cannot reproduce this on my XFCE ("GTK-only")
environment.

I notice in your video that you seem to use some form of a Qt theme bridge for
GTK applications. Perhaps a bug may be in there?

Alternatively, does simply installing wx 3.0.2 resolve your issue?