set a zvalue ridiculously high by default, since comboboxes always have to pop their dialog over the other idgets. mnual adjusting will still have to be done in the case of multiple comboboxes stacked

BUG:38981

svn path=/trunk/KDE/kdelibs/; revision=1061620

widgets/combobox.cpp

@@ -139,6 +139,7 @@ ComboBox::ComboBox(QGraphicsWidget *parent)
     d->lineEditBackground = new FrameSvg(this);
     d->lineEditBackground->setImagePath("widgets/lineedit");
     d->lineEditBackground->setCacheAllRenderedFrames(true);
+    setZValue(900);
 
     setAcceptHoverEvents(true);