If I do a search and then click back, the button still says 'searching...' and I can't do another search. If I then click refresh it goes back to 'find people'

If I do a search and then click back, the button still says 'searching...' and I can't do another search. If I then click refresh it goes back to 'find people' but doesn't work. I need to click in the title bar and press enter to do another search. Firefox 3.6 linux.