different "addChild" behavior of q3scrollview and qscrollview of qt3

The attached code ran just fine under Qt3, but under Qt4 it doesn't.
The code should create a table of buttons in a scrolled window. Under Qt4 it is blank. It turns out that when "this->addChild(w)" is called affects the results. In it's current position the scrolled window has blank contents. If it is called prior to the "new Q3GridLayout" call, the buttons are mispositioned. If it is called at the very end of the routine, the widgets are correctly placed.
In Qt3, it could be called at any time with the correct results – as it should. This needs to be fixed to make Qt4 more Qt3 backward compatible and also because correct layout should not depend on when "addChild" is called.