On OSX, Limewire's developers have made a rather interesting choice as far as window redraw update events are concerned: rather than stick to the boring, conventional path of redrawing portions of the window only when the content in them changes (thereby eliminating needless drawing and keeping things running quickly), Limewire instead opts to constantly redraw the entire window over and over again as fast as possible even if no content has changed. You can verify this yourself using QuartzDebug, part of Apple's Developer Tools.

This is (one of the reasons) why running Limewire brings the entire system to a brisk -- but aerobic -- crawl and is, in a general sense, a unique piece of software as far as usability and user experience are concerned.

Fortunately, if hide the window or completely obscure it with another window (from another application: any will do because none of them have chosen the interesting and special window update strategy that Limewire has), the OS will optimize out the update (some might say "intelligently optimize out the update") because it wouldn't change anything and would simply waste CPU cycles (an example of the equally viable alternative to "always draw everything all the time").