Erasing on transparent widget

I have a widget with a transparent background.

setAttribute(Qt::WA_OpaquePaintEvent,true);
setPalette(QPalette(Qt::transparent));

I draw some stuff on the widget

QPainter p(this);
p.fillRect(0,0,10,10,Qt::black);

I would now like to erase the rectangle so that the area is once again transparent and the widgets underneath show through. I can't seem to figure out out to do this.

p.fillRect(0,0,10,10,Qt::transparent); doesn't work.

Any ideas?

I am not sure how it is with transparent color, but have you tried to play around with QPainter::setCompositionMode()?

Hi Lykurg, thanks for the reply.
I've tried every composition mode. None seem to work.

setAutoFillBackground(TRUE);

or try:-
setAttribute(Qt::WA_TranslucentBackground,true );

No luck :(

Current setup:

setAttribute(Qt::WA_OpaquePaintEvent,true);
setAttribute(Qt::WA_TranslucentBackground,true);
setAutoFillBackground(true);
setPalette(Qt::transparent);

calling p.eraseRect... doesn't seem to erase anything

Anyone? Please :(