This conversation has been merged. Please reference the main conversation: Lightroom 4.1 very slow performance in develop mode
In the Develop module, adjusting any adjustment slider often causing the whole panel to grey out and jump or jitter. Often the mouse fails to 'grab' the slider and the adjustment doesn't get made.
I suspected several things so removed Windowblinds, reinstalled my AMD 5700 series driver, removed Catalyst manager and rebooted. LR behaved itself for a while then gradually the problem became worse till it was unusable. I also noticed the 'Loading' popup appeared more and more.