Two menus may overlap when openMenusOnHover is set to true

[a-yumashin]

There's an issue when openMenusOnHover is set to true.
Imagine the following menu structure:

RootMenu
    SubMenu_1
        Item_1_1
        Item_1_2
    SubMenu_2
        Item_2_1
        Item_2_2

We click on RootMenu, then click on SubMenu_1 --> submenu with items Item_1_1 and Item_1_2 is open.
Then we move mouse pointer over SubMenu_2 --> submenu with items Item_2_1 and Item_2_2 is open (because openMenusOnHover is set to true) BUT submenu with items Item_1_1 and Item_1_2 remains open, so these two submenus overlap (looks ugly).

Expected behavior: submenu which was open on click (with items Item_1_1 and Item_1_2) must be closed when another submenu is open on hover (with items Item_2_1 and Item_2_2). Two submenus should not be open at the same time.