Design tab's buttons don't have tooltips

Problem

The Issue Design tab features several buttons but none of them have tooltips. This makes it difficult for anyone not familiar with the UI to be productive. The archive (?) button's icon recently changed. Anyone already familiar with the button's new icon may risk clicking the new button but someone not familiar with it may not be so confident.

Proposal

Add tooltips to these buttons so that their purpose is discoverable without risk to the user.