I have a CSplitterWnd with two panes, A and B. In each pane, there is a CTreeCtrl. I want to be able to expand a node in the B tree control when the user clicks to expand a node in the A tree control. I want to save the user the step of expanding both CTreeCtrl. Sort of a "synchronized" Node Expansion. Is there some way to send a message from the A-pane (or CTreeCtrl-A) to the B-Pane (or CTreeCtrl-B) and tell it to expand?