Mouse select very sticky in Firefox 12
Since upgrading to v 12 on 2 machines one XP the other Windows 7 when I select in twitter Firefox acts as if the left button has been either held down or clicked twice. Sometime in Yahoo mail I select a folder and it open the folder then as the moves the list of folders opens the folder which is now under the cursor. In Twitter simply crossing over a message can cause it to be selected. This happens on 2 machine with different OS and only since upgrade to 12 doesn't seem to affect other apps just firefox.
Wšykne wótegrona (2)
It's likely caused by one of your extensions. See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.
If that's the cause I'd expect lots of others to be experiencing the problem as I don't have any exotic add-ons installed.