UI disappears when restoring from minimized
Symtom: UI / Content disappears after minimizing and restoring window at OSX Mavericks, sound still playing. Window doesn't show when selecting 'view all windows' for VLC at dock. Sound still plays. React to play/pause from dock menu. Switching to fullscreen make window visible, and set it to full screen. Window disappears when returning to normal mode
Steps to reproduce: 1: start playing video 2: minimize window 3: restore it from dock
Version: 2.1.0. OS: OSX 10.9 Mavericks HW: Macbook Pro 15 2010/mid