Comment 2 for bug 632897

Hi Michael,

Do you happen to be using the touch pad on your laptop? If so... many touch pads interpret a rapid double tap as a mouse click and hold. If you happen to be accidentally double tapping on the touch pad just before you move the cursor to the edge of the screen that would explain the behavior you are seeing.

If this is what is happening to you then you can control this behavior here: System -> Preferences -> Mouse -> Touchpad.
Under the Touchpad tab there are several options, one of which is "Enable mouse clicks with touchpad".

If you are not sure about this... you might try un-checking "Enable mouse clicks with touchpad" to see if the problem goes away.