@NigelParsons4560 wrote:
I click on my wall, drag the end of a witness line to a new point and the whole thing disappears, preventing me from changing the value of the witness line.
Also, I'd like to be able to add a witness line. is it possible?
Not sure I fully understand your first issue, but to change the length of a wall or any item, Pick that item then click on the dimension and type in the length.
For adding witness lines pick the dimension and then on the Ribbon Click edit witness lines. That will allow you to add or subtract witness lines from that dimension string. See attached
