Show left edge tag for unassoc AD/DA channels

[MichaelHuth]

While the HS0 and HS1 area is tagged, the unassociated channels (here AD2) has no tag on the left. It wold be good to have a tag at the red marked area as well, such that it is clear that the trace is unrelated to HS1.

Since the tags HS0 and HS1 actually refer to vertical ranges, I would also suggest to underlay them with a color shaded rectangle.

[timjarsky]

Just add UA and no vertical color bars.