Dear Hans,
The 0.43 version is very alpha. 0.42 is beta, so we appreciate bug reports like this so we can fix the final bugs before release. I think I fixed this problem with this commit: http://pure-data.svn.sourceforge.net/viewvc/pure-data?view=rev&revision=...
Please try downloading tomorrow's build and see if it works for you.
I just replaced the pd.tk in 0.42.5-extended-20100219 and the problem is solved.
Thanks, Lorenzo