Are you using a custom TreeControl or a custom TreeControlUI? Which API(s) are you using to manipulate the Tree control.

Is it possible that the Tree control in the Dialog is not the same one that you are adding/removing nodes from?

If you resize the dialog in question, or you move another window over it, just to invalidate its client area, do you see the expected result? If yes then it has to do with the TreeControlUi not redrawing itself.

See if detaching and then reattaching the TreeControl fixes your problem? If your TreeControl is in a graphical hierarchy, then you can call temporarily replace it with say a Fill object and then replace the Fill object with your tree control.

let fill:Fill = {Fill}
 
{myTreeControl.replace-with fill}
{fill.replace-with myTreeControl}
 

If this works then this means that the TreeControl is failing to inform the UI that its state has changed.

I am asking these as the information provided is not enough to guess what might be the cause of the problem you are seeing. We will be able to help you much better if you can post some code that demonstrates the problem.

Message was edited by: Kamal