Marking part of a sequence for copy/paste or playing

[Chordian]

Being able to mark part of a sequence with Shift and cursor keys, or marking with the mouse. The marking would be visible in all three tracks although more clearly/colorful in the currently edited sequence.

Things to do with such a marked block:

1. Copy it for pasting into the same or another sequence. This might not be used much and could be moved to a different issue while only doing the next step.

2. F2 now temporarily play-loops only this block. Cool while adjusting sounds for it. As soon as the block marked is cleared away, F2 returns to its usual behavior.

[Chordian]

This is a task migrated from workstreams in Slack.

[strbm]

After using SF2 for more than a year now, I would say extending copy-paste features should be a priority. It would spare tremendous amount of time if copy-pasting a marked part of a sequence could be pasted into the same or another sequence.