beans don't communicate

Hi,
I have an applet which contains (amongst other things)a tree, and a panel containing a tabbed pane. These are seperate beans. On change of value of the tree, I want some text on one of the panels to be updated.
So, in the valueChanged method of the Tree bean, I have the lines :
TabbedSummaryPanel tabSummary = ((TabbedSummaryPanel)topLevelApplet.getResultsPanel().getTabbedPane().getComponentAt(3));
tabSummary.setText(myCurrentPortfolioPath);
I know the setText method gets called because I put some debug in the method, but the text doesn't get updated.
I know the variable myCurrentPortfolioPath has the correct value at this point.
I can get the text to update quite happily via the stateChanged method of the tabbedPanel bean.
Any ideas ?
Thnks,
kate