Repaint QTreeWidget

[AceTheFace]

Hi,

I'm experimenting with qtjambi at the moment and I'm writing a little Jabberclient.
For the display of the roster (contact list) I'm using a QTreeWidget.
I've implemented a listener to react on any events which affect the roster:

public void presenceChanged(String user) 
			{
				QTreeWidgetItem parent = new QTreeWidgetItem();
				parent.setText(0, user);
				getTree().addTopLevelItem(parent);
                                System.out.println(user);
			}

public void presenceChanged(String user) 
			{
				QTreeWidgetItem parent = new QTreeWidgetItem();
				parent.setText(0, user);
				getTree().addTopLevelItem(parent);
                                System.out.println(user);
			}

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The listener itself is working correctly, but after initially connect to the server (so the listener is called >50times), my QTreeWidget is only showing the first 3-4 items. After clicking on the column-header for resorting the Tree-Items all Items were shown. So this seems to be a repaint-problem.
I've tried to add "getTree().repaint()" or "getTree().update()" within the listener, but none helped.
The debug-ouput is "QObject::connect: Cannot queue arguments of type 'QModelIndex'", but I have no idea if this is part of the problem above (I'm new to QT at all).

Any hints? Thx.

Greets,
Ace