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For the VI that is going idle, why not just use the VI Invoke Node with the Front Panel:Close in its ChangeView event handler. Then for the VI that is going visible, use SubPanel Invoke Node with Remove VI followed by Insert VI in its ChangeView event handler. I would add a Clear Errors in between in case there is nothing in the subpanel. You might also add a Front Panel:Close in front of all of this in case the VI is already being displayed somewhere along with a Clear Errors in the event it is not currently visible. Your race condition you describe would not occur. However, your user could go click happy and keep changing views faster than the clients can update. It may happen that the last view desired is not the one that ends up showing simply because the last one clicked processed the event fast. I personally would not bother handling that use case. I also agree with James, that you should pass in the reference to the subpanel and not store it. My apps have lots of subpanels. Front Panels are swapped around all the time. Each user wants to see things a bit differently.