long running paint + menu hole

Hi,

I have a MainWindow with drop down menus:

Code:

---

...
    redrawAct = new QAction(tr("&Redraw"), this);
    connect(redrawAct, SIGNAL(triggered()), this, SLOT(redraw()));
 
    redrawMenu = menuBar()->addMenu(tr("&Redraw"));
    redrawMenu->addAction(redrawAct);
...

---

When I select that "redraw" menu the painting starts to a Pixmap and so is not visible, but the disappeared redraw menu leaves a hole in the window, until the pixmap is painted.

Is that hole avoidable?

This is a picture:
http://www.esnips.com/doc/d24bf3f2-1...f31a463af3/ret

What does redraw() actually do? Could we see some code?

PS. Attach images directly on the forum, please.