Selected Feature Not Present in Attribute Editor

I've found in some circumstances that, while editing in ArcMap, I select a feature from among the classes in the edit workspace and that feature does not appear in the attribute editor. If I choose "List by Selection" in the Table of Contents the feature is listed as selected -- but its not in the Attribute Editor.

I've made sure that the thing I'm selecting is in a class that's being edited. The database in question is a File Geodatabase.

Any thoughts on what could lead to such a case would be much appreciated... I feel I'm likely missing something simple.

Thanks,
Ed