Summary: See PHI251. Ref T13137. - Replace the perplexing text box with a checkbox that explains what it does. - Mention this feature in the documentation. Test Plan: - Clicked/unclicked checkbox. - Read documentation. - Used an existing checkbox control in Slowvote to make sure I didn't break it. Reviewers: amckinley Reviewed By: amckinley Maniphest Tasks: T13137 Differential Revision: https://secure.phabricator.com/D19433