My experience almost exactly mirrors of OzPheonix. I haven't been able to find the exact pattern yet, but it does seem to be related to mousing between windows. (I'm using keyclone and keyclone's maximizer). Part of the difficulty with this whole runner issue is that there are any number of things that can be user related to cause it. Most of the time I get it... by far most of the time, it's becuase of a 1-dee-ten-t error. But occasionally it happens, and I know it's a bug of some kind.

At first, when it happened, I was having a VERY difficult time getting the runner to stop. I could hold down the "back-up" button and the runner would stop, but as soon as I released it, off-he'd go again, so I know for sure it's not an auto-run issue. (Backing up turns off auto-run) I finally figured out that, strange as it seems, if I click back over to one of the other windows, (one of the windows that doesn't have the runaway), the the runner will stop.... weird. But I haven't been able to replicate the issue consitently.

Knobley