Add tooltip to Delay button

[jidanni]

At the top of the screen the user see a mysterious "Delay" button.

Curious, they click it, only to find themselves looking at an even more mysterious giant lists.

• The button should have a tooltip, explaining what it is for.
• The list should have headers, saying what they are all about.

Yes I'm sure they are documented elsewhere already. But they should be documented as above too.