Display Modes
These are the standart viewport display modes you know from 3DSMax.
While skinning, it is best to have 'Shaded Weights' and 'Edge Display' turned on
Shaded Weights:
Toggle Shaded Weights Display.

X-Ray:
Toggle X-Ray (see through) Display Mode.

Edge:
Toggle Edge Display Mode.

Wire:
Toggle Wireframe Display Mode.
