The compilation of this class failed on a Windows / 64 bit / VC9 / Qt 4.7 Dart Client.
The error message was:
..\..\..\..\MITK\Modules\QtWidgets\QmitkDataStorageFilterProxyModel.cpp(76) : error C2440: 'initializing' : cannot convert from 'std::_Tree<_Traits>::const_iterator' to 'std::_Tree<_Traits>::iterator'
also see the cdash output: http://cdash.mitk.org/testDetails.php?test=9439131&build=502464