I have asked, and searched all over and can not find an answer.
Using XP Pro SP3, and all updates I have had this issue for many revisions of Firefox. This is not a new issue. Here is what happens. Many sites I go to, especially sites that require a login like GMAIL and AVSFORUM, etc are VERY slow with the Toolbar 4.6 active. When it logs into my GMAIL account it takes a long time to answer and when my mail shows up, it takes about 15 seconds before it lets me click on anything. The same thing happens when I go to log out of GMNAIL. It can take 15 seconds before it logs out and lets me go to another URL...even google. com. In fact, I even get a script error in the AVSFORUM for Local HDTV - US Thread Index, forums. When I disable the toolbat addon, it all works fine. It has gotten bad...even Netflix Queue is VERY slow. It seems like the toolbar 4.6 is doing too much checking!
I can't be the only one with this issue! I suppose I could try NIS 2011 but do not think that will resolve anything.