After much frustration I have discovered , among others , that placing a parallel line pays attention to snaps when completing the operation.
1: select the parallel line tool (two lines side by side)
2: move the "cursor" to an existing line.
3: left click, now the length of the line clicked is in the length box
4: press enter.
Now you have everything needed to place the new line, however
If your cursor just happens to be on a running snap, say the mid point, the line does not get placed where you would expect to be. It just disappears into nowhere.
Ok, turn off snaps, ugh, thousands of clicks. The draw parallel line tool should be smart enough not to do this, or am I the retarded one?
There are other anomalies, I will put in other posts.