I am using two stacked monitors on a mac mini. I like to have the browser dragged across both screens. Any keypresses of any kind when firefox is open cause the broswer to resize to only the top window. Any idea on what might be causing this?

Additional info: Chrome, Opera, and Safari have a similar resizing issue. Except it does not happen with text input, but rather happens whenever a bookmark is clicked or a link is opened in a new tab.