IE9 / IE10 / IE11 - reponse to dirty page warning is ignored

• Edit a page
• Enter some text
• Press the browser 'Back' button
• You get a dirty form warning -> click "Stay on page"

Expected: You stay on page (in the editor)
Actual: The back action takes you back to view page, cancelling the editor session, and irretrievably losing any text that was entered.