Why i have to click timer toggle button more than once?

Hi there! I use toggl with Firefox 2.0.0.4. The timer button is square shaped and gets visible, when "mouseover, but when i click the button on the corner, not on the center, it doesn't toggle the timer. I can toggle the timer only, when i click the red area of the button - it took me 3 weeks to understand why sometimes i have to click more than one time to toggle the timer :P