I've found if you disable the Compiz window decorations the "snap-to-windows" function actually works great and you can switch windows with the launcher and alt-tab! Of course, window decorations are pretty nice to have, so it's a pretty useless workaround - if it can even be called that.
But at least it's clear that there's something wrong with the window decorations. My guess is the shadows, but they are impossible to turn completely off (as fare as I can tell), so I can't be sure.
I'm also affected (and frightened to find out that this bug has been around since Natty). I described my experience here: https:/ /bugs.launchpad .net/unity/ +bug/834248
I've found if you disable the Compiz window decorations the "snap-to-windows" function actually works great and you can switch windows with the launcher and alt-tab! Of course, window decorations are pretty nice to have, so it's a pretty useless workaround - if it can even be called that.
But at least it's clear that there's something wrong with the window decorations. My guess is the shadows, but they are impossible to turn completely off (as fare as I can tell), so I can't be sure.