I have about a million of these and similar log entries: WindowServer: _CGXRemoveWindowFromWindowMovementGroup: window 0x1d is not attached to window 0x4d

I have about a million of these and similar log entries: WindowServer: _CGXRemoveWindowFromWindowMovementGroup: window 0x1d is not attached to window 0x4d My El Capitan installation is fresh. Didn't help. I think reading the logs in OS X since Yosemite, does make OS X feel buggy and it should probably not work as well as it does. :-/