Strange style of QtCreator

See the attached screenshot for 2 instances of running creator.

On the left there is a creator that comes from the installed package. On the right there is a creator built from sources by myseft.

Looks like styles used for both instances of creator are different (compare checkboxes).

The strange thing is that left creator's lineedits looks disabled when they are not in fact - they all have grayed background, what is misleading.