When a popup menu is open, key input is still dispatched to other controls meaning that for example in a tree control, it is possible to right click on a node and open a popup menu, and then delete the node the context menu was opened on (by pressing delete key and handled in the treeview's key up/down/press event to delete the selected node) while the popup menu stays open. This is also the case for barpopupbuttons (ie main menu).
