here's a quick thought:
why should a root-window left-click hide *any* menus at all?
rational:
we have the concept of the torn (persistent) sub-menu.
only a right-click hides a torn sub-menu.
why not employ only the right-click to hide *any* desired menu?
e.g. #1:
right-click the root-window to access the topmost-menu.
right-click the topmost-menu to hide the topmost-menu.
e.g. #2:
right-click the root-window to access the topmost-menu.
left-click-drag to tear away a menu.
right-click the topmost-menu to hide the topmost-menu.
right-click the torn menu to hide the torn menu.
just an idea.
