Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7) Gecko/20040719 Firefox/0.9.1+ rightclick brings up the (alert) popup .... and the context menu at the same time. The Contextmenu works.
I get same as comment 1 in 1.7 on OS/2, except that after dismissing the alert/menu, the alert redisplays one time.
I have this issue with Firefox 1.0.1 with no extensions. New browser windows are launched by some web pages with no context menus even though "Disable or replace context menus" is clear (unchecked). Example http://www.wjr.com - "click here to listen"