It's about staging hunks. Plain compare does not allow me to stage anything.

I picked a bad example. It's possible that the first red line came from whitespace differences (arrows visible, indicating I can copy the difference). Here's a better one: The changes in the third block have been staged already. The editor still shows differences (Index being different to HEAD). The last green line (different to HEAD) has only a slight visual difference compared to the first green line (Index having one line more than Working Tree). This is confusing and makes comparing differences harder than it could be.

True. Just tried it. Works. But as you see this effect is very subtle. I was not so clever to delete the message before. Maybe it's similar for others.

I know this trick now. But maybe you want to make it more obvious for future users.

A example for a long branch name:

custom/JDK8/dr-21654-some-jira-issue-title

Depending on the available space, shortening could be more aggressive. Everything from
custom/JDK8/dr-...jira-issue-title
to
cust...itle

could be possible.

The main aim should be to leave some space for the commit message.

Right. Didn't see it. Mine is a duplicate.