I posted a bug report about this in October that was confirmed by Dan Letecky (forums.daypilot.org/Topic.aspx/1156/firefox_3610_for_mac_context_menu_issue#3788). This is still a problem in Firefox 4 for Mac, and I was just wondering if there was any planned release of a fix? This issue is still occuring on the latest version of the Calendar demo on this site.
Gary, it's in the queue. I hope the fix will be available soon.
Thanks for the update Dan, sorry to keep going on about it.