Develop module sliders changed to grey from their previous colors and gradients. Any way to change back?
If this is after an OS upgrade to Maverick on a Mac, then I believe it is a known issue for LR 4.
And the solution is to upgrade to LR5.2 (or back out of Mavericks, or just accept the new situation).
Yes, I just upgraded to OSX Mavericks this morning. It's not really a huge deal, but it does slow down my workflow a little.