[Bug 31598] Re: delayed mouse button release causes menus to close

[David Balažic]

This is not a bug, but a feature ;-)

Menu selection can work in two ways :
 - "classic" : you click on menu, click on sub-menu and finaly click on the actual submenu item
 - "single click" mode, you press the mouse button on the menu, move to the submenu, move to the sub-menu item and only the release the button

The choice is made with the length of the first click. If it is short,
"classic" mode is used. If it is not short, then "single click" mode is
used.

This is the same in GTK+, Firefox, even Windows.

-- 
delayed mouse button release causes menus to close
https://launchpad.net/bugs/31598