No "Navigate Out" Warning When Editing Issue

On this very page (Create Issue, Step 2 of 2) I am not warned if I navigate away from the page accidentally (eg hitting back, or clicking a link, or opening something in this browser from an external program, or a mouse gesture). If a navigate happens, all my editing is lost.

There should be a standard warning issued upon the appropriate HTML event for navigate-out, asking of whether I am sure I want to discard my editing, OK|Cancel.

It would be nice to also have this feature at all the pages where appropriate, as data loss happens for me from time to time.