Weird Console log spam when switching spaces

Question

I'm on an iMac running OSX Mountain Lion 10.8.5, so whenever I switch spaces I see a bunch of these entries in my console log as part of system.log.

30/11/13 12:42:06.056 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6c6
30/11/13 12:42:06.056 PM Dock[208]: find_shared_window: WID 1733
30/11/13 12:42:06.056 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6c5
30/11/13 12:42:06.056 PM Dock[208]: find_shared_window: WID 1732
30/11/13 12:42:06.056 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6c4
30/11/13 12:42:06.056 PM Dock[208]: find_shared_window: WID 1731
30/11/13 12:42:06.056 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6c3
30/11/13 12:42:06.056 PM Dock[208]: find_shared_window: WID 1730
30/11/13 12:42:06.056 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6c2
30/11/13 12:42:06.057 PM Dock[208]: find_shared_window: WID 1729
30/11/13 12:42:06.057 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6c1
30/11/13 12:42:06.057 PM Dock[208]: find_shared_window: WID 1728
30/11/13 12:42:06.057 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6c0
30/11/13 12:42:06.057 PM Dock[208]: find_shared_window: WID 1727
30/11/13 12:42:06.057 PM Dock[208]: CGSGetWindowTags: Invalid window 0x6bf

I use the following programs that may interfere with it, but I tried monitoring after disabling each of them, it doesn't help.

• TotalFinder
• HyperSwitch
• BetterTouchTool

Also, strangely if I alt-tab between applications this does not happen. Only if I move between spaces using the mouse (two-finger swipe) or keyboard (ctrl+left/right), it happens. I tried restarting the dock (killall Dock) and the finder, restarting my computer and so on. None of those help. WindowServer CPU usage inside Activity Monitor seems to be quite normal as well.

Anyone have any idea of what may be causing this? Any insight would be much appreciated. Thanks a lot!