Imported a figure. Inserted and rearrranged bones from excisting character. Assiging the right groups to the bones. But with changing some body angles not all body parts "follow". For instance left forearm. All transform parameters work good, except bending. Some polygons do not follow and are stretched like a gummy band. Tried everything. Welding. Changing bones. Deleting hand. All left arm polygons are selected in the left forearm group. If I do Side-side first (no problem) and then Bend, results in the same problem. In other words, I cannot bend properly. In Setup room, the bones do respond as they should.

What am I overlooking.