Rated 5 out of 5 stars
Reminderfox is the most essential addon for Firefox, for me. It replaces my diary and ensures I never forget an appointment.
Unfortunately tooltip is buggy on my PC with FF4 (with rel 126.96.36.199.1, Win 7 32) and hovering over the reminder ribbon doesn't work to show the RF tooltip list. No doubt this will be remedied soon.
I have the same configuration and do not see the issue with the reminder ribbon. Send us an email (personal emails are listed on the Developers tab here, or reach us as firstname.lastname@example.org) and we'll help get the issue resolved.