Feedback on channel-specific annotation

[mscheltienne]

Describe the problem

Following #255, a bit of feedback on the great new feature!
@nmarkowitz Those points are not high priority at all, but if you need a break from a different problem, each one might be a short PR ;)

• (1) Hovering highlight of the annotation is lost when a channel-specific annotation is added with (shift + left click). The hovering highlight comes back after the mouse exit the annotation area and comes back on it.

screencast1.webm

• (2) Moving a channel specific annotation on a regular annotation merges them together and turns the union-segment into a channel specific annotation.

screencast2.webm

• (3) Moving a regular annotation on a channel specific annotation is not working. Visually, we get a single region with part of the region having channel-specific annotation. If the region (annotation) is then deleted, the channel-specific annotation remain.

screencast3.webm