Recently in the Review queue for closures I found several seemingly perfectly on topic questions. Only when I opened them outside the queue I saw comments on answers that made clear that the question was probably about a (well-known) bug.
So I'd ask whoever initially votes to close a question (knowing facts that are not obvious from the question itself or comments on it) to add a comment as a hint.
As an example (the one that actually triggered this question) see: Why Ctrl+Shift+Alt+Down won't move a window one workspace down in 13.10.
It looks like a perfectly on topic question in my eyes. Only doug's answer (and comments on it) say it is/might be about a bug. As Braiam stated correctly our votes should evaluate the question only - then how did my fellow close-voters reach the conclusion of off-topicness?