Why can't I set max background FPS?

Before when I was camping for the Time-Lost Proto-Drake, I had 4 windows opened (4 accounts and background FPS on them all set to 0 to make them take up as little power as possible. Now though as I get ready to initiate the Aeonaxx camp, I tried to set the background fps to 0 again but it seems to stay at max. When I leave the window the slider turns grey and default max.

What is this? Is it due to my new screen causing this trouble? I cant have 3 windows of WoW opened in the background with max FPS...

First thing Id do is check the trinity of Cache, Interface and WTF. If those dont make a difference, my next guess would be to check for write-protection.

FAIL (the browser should render some flash content, not this).

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