Fixed: Menu disappears when opening a submenu

Previously when opening a submenu from a menu, the main menu disappears because a issue with the poolMenuWindow.
This PR fixes this bug.
It also handle more properly the case when an user is making several right clicks on a responder (origin problem with the ghost menu).

Fixed #1887
Merge pull request #1982 from Dogild/MenuFix

Fixed: Menu disappears when opening a submenu