/usr/bin/unity8:11:data:qGetPtrHelper:d_func:QCoreApplication::notifyInternal:sendEvent

Backtrace says

#0 data (this=0x4) at ../../include/QtCore/../../src/corelib/tools/qscopedpointer.h:135
#1 qGetPtrHelper<QScopedPointer<QObjectData> > (p=...) at ../../include/QtCore/../../src/corelib/global/qglobal.h:961
#2 d_func (this=0x0) at ../../include/QtCore/../../src/corelib/kernel/qobject.h:110
#3 QCoreApplication::notifyInternal (this=0xa16f00, receiver=0x0, event=event@entry=0xbed03b90) at #4 0xa8bf76dc in sendEvent (event=0xbed03b90, receiver=<optimized out>) at /usr/include/arm-linux-gnueabihf/qt5/QtCore/qcoreapplication.h:228
#5 TouchRegistry::TouchInfo::notifyCandidatesOfOwnershipResolution (this=this@entry=0x108ad60) at /build/buildd/unity8-8.02+15.04.20150603.1/libs/UbuntuGestures/TouchRegistry.cpp:500

Seems that candidates[i].item in
          QCoreApplication::sendEvent(candidates[i].item, &lostOwnershipEvent);
is a null pointer

This bug was fixed in the package unity8 - 8.10+15.10.20150803-0ubuntu1

---------------
unity8 (8.10+15.10.20150803-0ubuntu1) wily; urgency=medium

  [ Kevin Gunn ]
  * No change, rebuild for gcc5

  [ CI Train Bot ]
  * Resync trunk. added: po/cy.po

unity8 (8.10+15.10.20150729-0ubuntu1) wily; urgency=medium

  [ CI Train Bot ]
  * Resync trunk.
  * allow opening the manage dash area by clicking with a mouse on the
    arrow label (LP: #1431564)

  [ Daniel d'Andrada ]
  * TouchRegistry: remove null candidates from list of candidates (LP:
    #1473492)

  [ Lukáš Tinkl ]
  * Fix power dialogs on desktop
  * Provide DBUS compatibility with various session services
    (suspend/hibernate, lock/unlock, screensaver, etc)
  * React on PrtScr keyboard shortcut for taking screenshots on desktop
    (LP: #1474149)
  * launcher parity: close apps from quicklist (LP: #1457201)

  [ Michael Zanetti ]
  * Implement first edition for a desktop Alt+Tab spread
  * drop the gcc-4.9 dependency (LP: #1452348)

  [ Mirco Müller ]
  * Added corresponding tests and visual tweaks to a launcher-item's
    progress-overlay.
  * Added corresponding tests and visual tweaks to a launcher-item's
    progress-overlay.
  * Implemented alert/wiggle feature for launcher-icons.
  * Implemented alert/wiggle feature for launcher-icons.

  [ handsome_feng ]
  * makes left swip reset the search string. (LP: #1413791)

  [ handsome_feng<email address hidden> ]
  * Don't expand indicators when tap to return to call. (LP: #1453217)
  * makes left swip reset the search string. (LP: #1413791)

 -- CI Train Bot <email address hidden> Mon, 03 Aug 2015 14:17:33 +0000