Basically, I would like to be able to set a default state for the menu (which menu is open and which menu item has focus) in code behind (like the Page Load event).
The menu would start off showing the designated menu as open and the designated menu item would have focus but the user would still be able to hover over other menus to open them (the default open menu would then collapse).
If the user ends up moving the mouse off the menu without clicking anything, the menu would then automatically revert to the default state set in Page Load.
It would be great to just set the default state in code behind and have the menu reset to that state when it loses focus. You could also have a reset timeout so that the menu will reset after the mouse is off the menu for a set number of seconds.
A quick Google search shows that people have been asking for an easy way to implement this for years.