We've identified a bug that may cause, under certain circumstances, periodic freezes of the Firefox UI, in terms of a short freeze every about 9 minutes. This only affects a small amount of users, so, if you don't notice this behavior, you can stop reading.
UPDATE: Firefox 8 has been released, including the promised fix. Go grab it!
If you think you are suffering this bug, stay sure it will be solved in Firefox 8. In the meanwhile, here is a simple workaround to fix the issue:
- Install my Places Maintenance add-on
- Go to about:addons and open the add-on Options dialog
- Select the Expire operation and click Execute
- If you wish, uninstall the add-on (it's restartless, so the process is straight-forward)