@kain88-de 

You are right, both ways are workable and _expected_ result is the same. But difference is:
* in first case -- without `m_pTrackCollection->callSync` -- we do access to database in Main thread
* in first case -- with `m_pTrackCollection->callSync` -- we do access to database in `TrackCollection` thread

For example, **if we forget to access a DAO over `m_pTrackCollection`** we can get database access error (Such as it was previously with `LibraryScanner`. When `LibraryScanner` was scanning and you try to create playlist, you get error -- database was locked).

Also, unnecessary behavior situation **if we forget to access a DAO over `m_pTrackCollection`** can be UI freezing.