Comment 2 for bug 946285

StacktraceTop:
 operator() (h=..., this=<optimized out>) at /build/buildd/unity-5.4.0/plugins/unity-mt-grab-handles/src/unity-mt-grab-handles.cpp:859
 std::_Function_handler<void(const boost::shared_ptr<unity::MT::GrabHandle>&), UnityMTGrabHandlesWindow::restackHandles()::<lambda(const Ptr&)> >::_M_invoke(const std::_Any_data &, const boost::shared_ptr<unity::MT::GrabHandle> &) (__functor=..., __args#0=...) at /usr/include/c++/4.6/functional:1778
 operator() (__args#0=..., this=0x7fff2a931140) at /usr/include/c++/4.6/functional:2161
 unity::MT::GrabHandleGroup::forEachHandle(std::function<void (boost::shared_ptr<unity::MT::GrabHandle> const&)> const&) (this=<optimized out>, f=...) at /build/buildd/unity-5.4.0/plugins/unity-mt-grab-handles/src/unity-mt-grab-handle-group.cpp:193
 UnityMTGrabHandlesWindow::restackHandles (this=0x295f730) at /build/buildd/unity-5.4.0/plugins/unity-mt-grab-handles/src/unity-mt-grab-handles.cpp:659