TB freezes when changing key trust in Enigmail 1.2

Yesterday I upgraded my portable Thunderbird to 5.0. Actually, after issues with the Lightning Addon I choose to reinstall it completely.
I use TB with GPG Portable for TB (1.4.11) and Enigmail 1.2. After setting everything up I wanted to change the key trust of one of the public keys. When choosing "Set Owner Trust" and changing and clicking okay TB freezes and does not recover. Only help is to kill it in the Taskmanger and restart.
I wrote an email to the Enigmail guys, but they say they don't have the problem (And I didn't make it to test it on my own on normal installation, maybe next week). So anyone else run into similar problem here or at least can reproduce it? And knowing the cause would be even better.
Btw. I can't say for sure if the problem hasn't been there in portable TB3.x and the corresponding Addons.

Edit: After upgrading my normal installation I run into the same problem and openend up a thread at the enigmail forum. See:
http://www.mozilla-enigmail.org/forum/viewtopic.php?f=3&t=780