Partial Screensaver

Have any of you guys ever seen a security camera monitor? You know, the screens that show the views from multiple cameras, each in its own little window with a black line separating them? Ever see one switched off? Those little black lines are burned into the screen, because, while the camera images are constantly changing, those black lines do not.

Or how about when you watch a movie on your computer, but don't think to put it on full screen because the viewing window is big enough? You disable the screensaver, or set it for the full length of the movie, so it doesn't activate mid-movie and interrupt your viewing, but forget to put it back to its original settings afterword? I've done this many a time.

But the truth is, I really want that screensaver going during the movie, because I don't want the rest of the screen, outside the viewing window, just sitting there, getting burned in. Or when I'm reading a lengthy e-book or news article, or a science journal or tech manual. The part of the screen with the text gets changed everytime I scroll or click something within it. But what about the toolbars, or the status bars? I don't want those getting burned into the screen.

What is needed is a partial screensaver, a screensaver that comes on at its regularly scheduled interval, but only affects the portions of the screen that aren't moving or changing frequently enough. Maybe something subtle, so it doesn't distract from what you're viewing, but just dynamic enough to prevent phosphor burn-in on older monitors.