fix test20b.py - wait for xprop to finish before continuing
fix test20b.py
- wait for xprop to finish before continuing

nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor