Help menu — What's This?

Arms the help cursor — the same thing as clicking ? in the toolbar, or pressing Shift+F1. The next click on a control opens the topic explaining it instead of doing that control's job.

Shift+F1 is the useful one to remember: it works without a menu, and it can be pressed while a menu is already open — which is the only way to ask about a menu item, since the help cursor would otherwise swallow the click that opens the menu.

Full behaviour is in The ? button.