try setting the following on the Toolbox window:
(beside your stylesheet declaration)
or another possibility: "QGraphicsOpacityEffect":http://qt-project.org/doc/qt-4.8/qgraphicsopacityeffect.html
But this also applies for the child widgets.
btw: This is no valid stylesheet declaration AFAIK.
[quote author="ChanchoCiego" date="1365190604"]Hello,
background-color: background: rgba(12,34,56,0);
Also a nice trick i used to do was setting the background color not to fully transparent but to something like this: rgba(0,0,0,1)
This almost has the same effect like transparency but it's not. Thus it's also treaded differently by the windowing system and may help you.