Drag and drop from some mscore file onto the mscore2 desktop symbol is without effect

I'm running the nightly build mscore.64bits-2014-10-20-09-35-dc48ff5.tar.bz2. In previous nightly builds it was possible to drag some mscz file onto the mscore2 desktop symbol (so the mscore file will be opened by mscore2), but since some recent nightly builds this is no more possible.