Intersect Morph Faces (Generate Edges within a Morph)
While editing a Morph, its shape may be transformed such that a single face is intersected by other parts of the Morph. At this point, the new (self-)intersection is not yet delimited by any edges.
If you henceforth want to treat such intersecting faces separately, use the Design > Modify Morph > Intersect Morph Faces command.
This command works on a single selected Morph only.