User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0 Build ID: 20121128204232 Steps to reproduce: Spell check multiple words in a single session of Firefox. Actual results: Each and every single right-clicked misspelled word is added to the suggestion and not removed until the browser is restarted. Expected results: Each new right-clicked misspelled word should be suggested upon and any previous suggestions should have been removed.
Could you try with a fresh profile, please: https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
Refreshed profile and the error was fixed. Going through installation of addons to try and pinpoint which one could have been the problem.
Safe mode is useful to debug issues about add-ons/bad prefs: https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
As for comment 2 it seems that the problem now if fixed. I'll close this but, please, feel free to add comments if you find the specific origin of the problem (which addon has caused this) it could be useful for other that have experienced the same.