imac jumps to other pages in safari without clicking mouse

I'm having a periodic problem...occasionally my imac jumps to the previous page without my telling it to. For example: in safari, I've moved the Magic Mouse to the top left of the screen - but b4 I click the arrow to go back a page it does it on it's own. (Or once, Aperture 3 close on it's own when I moved the Magic Mouse to the top left area...but never clicked anything.) Any ideas what is going on?

Are you accidentally 2-finger swiping to the left in Safari? That is the Magic Mouse gesture to go to the last webpage. As for the Aperture incident, I'm not too sure. The only mouse-related cause of that I could think of is if you have tap-to-click enabled. However, in order for you to do that, you'd have to have the app BetterTouchTool installed.

my imac jumps back as well

Hi,
I have the same problem with my imac. sometimes it jumps even when am not touching the mouse. It happens when I am playing scrabble or just looking at a webpage. Is it a problem with the mouse or the imac? Sometimes, it returns to the top site page and opens another page.