Hi Unikron! After long delay I just updated Unity to 4.3.4f1 and ran into the same issue posted here. I know this problem has been fixed in 2DTK 2.3, however I'm nearing the end of a project and still running 2DTK 1.92 Final, and I'd prefer to avoid migrating now if possible.
So, is there a reasonably-simple way for me to fix this in my local copy of 1.92 Final, perhaps just by copy-pasting in what you did for 2.3?
Or, if not, can you confirm that the only problem caused by this error is the loss of Undo/Redo? If need be, I can live without them for awhile, but not preferable of course.
Thanks for your help!