Hidden Lines (Not planned for)

No problem changing attributes or properties of lines from solid to dotted to represent hidden lines but is there an easier way than trimming an existing line than now falls behind and drawing a new with the correct properties.  For example is there a way of changing just a section of a line?

You can't change the properties of just a part of a line and still have it to be one entity. You have to break it up. Tools - Modify - Divide is the proper instrument for this. Select the line and then select the cutting point, probably an intersection, with snap intersection on. You can only do one cut per operation. Then change properties of the desired part. Maybe not less work than trimming and redrawing.

Got it..... I simply missed Divide.  Does exactly what I envisioned, separating a line into two parts.  Does have the advantage for this application that future selection permits deleting the whole line, which is probably the need.

I think you.