Insert Crystal fails with filter text

OK, I just submitted a crash fix (and David approved it) for a very weird bug.

The new Import -> Crystal feature offers a filter box. But if you type text in there, MoleculeFile::readMolecule fails. So my fix is a band-aid.

I can’t figure out for the life of me why typing text into the filter box stops reading. Anyone want to give this a try to find the underlying bug?