I didn't test this myself, and am still unclear with the root cause of the issue, but I trust @zhekov's explanations and the code look OK to me.
I however tend to agree with @elextr and @kugel-: merge it, but right after the release so we get testing. It's tricky as we always say this and then forget until next cycle, but maybe we can do better this time… And yeah, more and more distros seem to switch to GTK3 so Scope won't work there now.