Source Pro problem although tk1 and tk2 folder are deleted

With the first release on Muse 2014 I never had this font problem, which is described here:

Source Sans Pro not displaying in 'Design' mode

After updating to Muse 2014.0.1.30 the problem caught me too:

I closed Muse, located the tk1 and tk2 folders in my user library and deleted them:

But the problem shown in the first screenshot persists! Any hints, what I can do?