Well, let's try again. I do following:
- run MED 6.872 (from GS);
- create the cube;
- enter "bone mode";
- press "create bone";
- create 2 hinge points (and 1 bone);
- release "create bone";
- draw a rectangle around the hinge points AND THE BONE (now they all are red);
- enter "apply vertices mode";
- draw a rectangle around all the vertices of the cube (now they are red);
- want to press "apply vertices" but IT IS INACTIVE!!!!!!!!!!!!!!!
There is the same fignya in MED 6.873.
!!!H!!!E!!!L!!!P!!!.........................

Mistakes may be here coz my English in not perfect.