When editing a file with a window open under the editor window (i.e the Run, Debug, CVS, Messages, ToDo windows), each time a message (like "missing return statement") is displayed on the message line at the very bottom of the Idea window, the message box appears to grow by a very small, but visible, amount and when the message disapears the message box appears to shrink by the same amount. This change in size causes the Run, Debug, etc. windows to "bounce" as messages appear and disappear in the bottom message window as i type.
Environment: Mac OS X 10.4.7 G5
Of course this is not a very serious issue, but it is annoying. And I fixed it. Or maybe I should say: I found a workaround ;-)
In the lower right corner of my IDEA main window is a garbage collection icon. This gave me an idea:
Et voila, no more bouncing window!