Mouse position should not be taken into account for anything other than menus when a menu is open

So while a menu is open, only that surface should get mouse hover events.

That is how things work today. Do we want Design input on that?

This bug was fixed in the package unity8 - 8.15+17.04.20170216.1-0ubuntu1

---------------
unity8 (8.15+17.04.20170216.1-0ubuntu1) zesty; urgency=medium

  [ Albert Astals Cid ]
  * Make menus items close the menu when clicking on them (LP: #1657082,
    #1657399)
  * Clicking on an open menu closes it + test
  * Make the menus and submenus do not go outside the screen when
    popping out
  * Auto open submenus on hover (LP: #1657085)
  * Make the double click on a menu not be maximize the window below
    (LP: #1657079)
  * Make the MenuBar InverseMouseArea eat hover events when there's a
    popup open (LP: #1657763)
  * Make double click on the window decoration maximize (LP: #1657758)
  * Eat hover events when the launcher quicklist is open (LP: #1640776)
  * Remove TODO now that we require Qt > 5.5
  * Serialize two make targets that want to cp to the same target file
    (LP: #1660576)
  * Remove variable that is always false (LP: #1585910)

  [ Daniel d'Andrada ]
  * Consolidate launcher API checks

  [ Lukáš Tinkl ]
  * Fixes for activating minimized windows and restoring fullscreen ones
    (LP: #1656808, #1658937, #1658938)

  [ Michael Zanetti ]
  * move right edge push area up some levels so it can be used on top of
    the indicators
  * fix minimizing/restoring transitions (LP: #1658936)
  * fix some glitches with spread positioning
  * fix jumpy animation when closing an item from the spread
  * Show the wallpaper while the focused app is moving in staged mode
    (LP: #1648251)
  * Update the tutorial to mention the app drawer instead of the dash on
    long left edge swipe (LP: #1658932)
  * prevent hiding the launcher when the mouse hover event is eaten by
    the EdgePushArea (LP: #1657045)
  * properly invalidate the whole model (LP: #1658190)
  * stabilize OrientedShell test (LP: #1658994)

  [ Nick Dedekind ]
  * Added overflow support to application menus.
  * Updated menu colors

 -- Michał Sawicz <email address hidden> Thu, 16 Feb 2017 13:49:18 +0000