Firefox has changed the default functionality of the browser sidebar. Before in Mozilla, you could have tabs for different types of side bar content. Now, you can only have one sidebar type at a time. However, you can set a bookmarked page to open in your sidebar when clicked. This is how I am using the WordPress sidebar. It creates a small form version of the write form so you can surf the web and publish it. I particularly like this feature.
When WordPress upgraded to 1.5, they did some changes to the template layouts and apparently they added header tags that broke the sidebar function. I modified one of the pages and this is my test to see if I didn’t break a bunch of stuff.