Comment 1 for bug 1360843

I am also having this issue in 0.3 Freya. Alt-shift-tab works normally (and after using alt-shift-tab alt-tab works again until you stop switching), but otherwise alt-tab only switches between the last two windows. For me this behaviour has been spontaneous and hasn't gone away after a reboot; I've been running elementary for a few (3-4) days.