1. Xubuntu 15.04 OS; or
2. Parole Media Player;
when shifting cursor over black background of Parole Media Player, the cursor 'disappears.'
Must flick mouse around until one accidentally hits on the Parole sound adjustment button (white background).
Unpleasant 'lost' feeling & navigation hard.
Weird. Not sure what the problem is.
As it's free, I can live with it. ;)