What is the difference between Frozen and Locked in Project Manager?

Frozen and Locked is found in Project Manager under Element Marks.

Frozen and Locked both works in the same way, the difference is who is affected by them. Locked disables the element mark and drawing to be changed for other persons. Frozen does this for others inclusive of yourself. You can neither change the drawing or element mark if it is locked.

Figure 1: Frozen & Locked in Project Manager