When I first used my Ymessenger with my new firefox browser installed, I was having problems opening my Y!mails. Everytime I click the mail icon from my messenger, Internet Explorer browser always opens the page. So I decided to remove the Internet Explorer from my pc, then tried again. Nothing happened! It did not open any page, neither from IE nor Firefox.
At that point I thought the problem was with the YM version I am using. So I delete the YM and installed the YM beta. It worked! But the YM Beta is not working as good as the older version. I experienced frequent dropped calls and some connection problems. I was forced to go back to the older version and endure the agony of using two browsers whenever I use the Yahoo Messenger.
Until I figured out the answer. I am pissed of Buzzing and Calling Ringtom\nes from my chatmates, so I always edit the preferences and disabled all sounds from the messenger.
In order to use Firefox browser when clicking any icon from your messenger, you must UNCHECK the the Open links in a new browser window from the preference menu your messenger. To do this, you must clik the Messenger button from your YM, go to Preferences –> click General –> then UNCHECK the Open links in a new browser window then click OK.