You've fixed one problem and created another now: whenever I click the left button it gets stuck/selected in whatever OS/app button I am clicking (for example, if I click on iTunes to go to the next song, it activates fast forward instead).
Another example: you click on Sync to sync your iPad on iTunes, and the button just gets selected as if you were pressing the mouse button all the time without releasing.
This is always happening with the Magic Mouse, at least.
I haven't heard about this problem before. Are you sure you're not running any other mouse related software?