I have been able to replicate this issue multiple times now.
I will be in the middle of an edit session using 3 polygon feature classes and 1 point feature class. Each feature class has some feature in it. All features have have templates and I am not running any definition query. I will save and stop editing to Add XY Coordinates to the point feature class. I will resume editing but the only feature I am able to edit is the point feature class. The 3 polygon feature classes still have templates but will not display in the Create Features window. All layers are visible through this procedure. These are feature classes within a feature data set in a personal GDB The only way to begin editing the polygon features again is to restart arcmap.
attached are edit session prior to adding xy coordinates (image1) and after adding xy coordinates (image2)