Created attachment 243831 [details] Crash report As of r177821, when webkit remains off focus (covered with the windows of other apps) for a while, without an actual usage, it forecloses the entire app. Attached is the crash report.
Thank you for the report! I think that this can only happen when one of the pages uses a particular web API. Can you find out which page causes this?
<rdar://problem/19363508>
Lets close this unless you've still seen it somewhere