An onmouseup handler is attached to the following embed element, which loads a quicktime object that plays an mp3.

In Firefox 2, clicking anywhere in the plugin area (including the control bar) will cause the onmouseup event to fire. In IE7, Opera and Firefox latest trunk, it does not fire because listeners are attached to the embed element itself, NOT the plugin's area.

The Quicktime object scripting does not seem to provide any mouse event handling itself so, there might be a use case for this. However, FF 2 and IE6 might be the only ones that supports this. Also, this doesn't even work in FF 2 if you use the object element. It seems to be an embed quirk.