To reproduce:: * History -> Show All History -> Right click and delete all time periods * Open a new tab * Problem: Notice that some of the web page thumbnails shown are from the deleted history * Workaround: Restart firefox If I clean out my history with History -> Time range to clear: Everything, then all the old thumbnails are gone immediately. Tested with: firefox-21.0-3.fc18.x86_64
I've found similar bugreport on upstream bugzilla. We're going to track this problem there: https://bugzilla.mozilla.org/show_bug.cgi?id=774754