Scroll event over shell elements passes through

Scroll events also pass through the desktop spread background, hitting the window behind it.

This bug was fixed in the package unity8 - 8.12+16.10.20160627.5-0ubuntu1

---------------
unity8 (8.12+16.10.20160627.5-0ubuntu1) yakkety; urgency=medium

  [ Albert Astals Cid ]
  * Stop watching the old header item height once it's not our header
    anymore
  * LVWPH: cull the header item when not on view to save some painting
  * Adapt test to new mock behaviour
  * Don't let the mouse go outside the parentItem (LP: #1525350)
  * Use non deprecated package names
  * Mark system includes as such
  * Fix initialization order warning
  * Do not rely on deleteLater not crashing on null pointers
  * Add more headers of classes we use for automoc to be run
  * CardTool: Fix the fallback value to be a size and not an integer
  * CardTool: Include Ubuntu Components since we're using units.gu
  * Rework tst_PreviewRatingDisplayCreationRanges

  [ Daniel d'Andrada ]
  * Cursor: Let AnimatedSprite run only on animated cursors and while
    the display is on (LP: #1588873, #1594358)
  * Fix missing screenshot when orientation changes while shell rotation
    ongoing (LP: #1587796)

  [ Josh Arenson ]
  * Make PreviewRatingSingleDisplay visible again after editing a
    review. (LP: #1587097)
  * Correct errors in all png images to prevent libpng warnings.

  [ Lukáš Tinkl ]
  * Fix some smaller issues with OOBE wizard password pages (LP:
    #1590467)
  * Prevent mouse wheel events from going through shell elements (LP:
    #1536268)
  * Do not let mouse and wheel events pass thru the titlebar (LP:
    #1588424)
  * Hide the maximize window button based on size restrictions (LP:
    #1541982)

  [ Marco Trevisan (Treviño) ]
  * Unity8.conf: ensure MIR_SOCKET is set for future customers (such as
    the dash)
  * ClientIndicator: be more informative about loading failures for
    dynamically created objects

  [ Michael Terry ]
  * Stop unity8 from getting in a "switch-to-greeter" loop when locking
    on a desktop. (LP: #1593718)

  [ Michael Zanetti ]
  * set minimum window sizes on dash
  * displace application windows when the OSK would cover them

  [ Nick Dedekind ]
  * Force dash to always stay in the main stage. (lp:#1592404) (LP:
    #1592404)
  * Save the last surface stage on stage drop. (LP: #1579003)
  * Default portrait only apps to the side stage. (LP: #1573153)

  [ Albert Astals Cid, Andrea Cimitan, Michał Sawicz, Nick Dedekind ]
  * Added live video playback in dash previews

 -- Michael Zanetti <email address hidden> Mon, 27 Jun 2016 18:48:59 +0000