Migrating Global Tab Settings from QtCreator 2.3 into 2.4 doesn't work as expected

To reproduce:
0) Remove QtCreator.ini and qtcreator/codestyles folder (inside .config/Nokia)
1) Run QtCreator 2.3
2) Create a new session and a new project
3) Set global tab settings to e.g. 6 (tab and indent)
4) Close QtCreator 2.3, open 2.4
5) Load the session from point 2
6) Tab settings are 4 (bug). Trying to change global tab settings to 6 doesn't influence the editor (need an explanation in release notes - now you do that in C++ | Code Style Settings)