The current hit region specification doesn't state what events are routed to the fallback content. Probably only mouse and touch events should be intercepted and forwarded.
Thinking a bit more about this feature, it's a bit weird how events are rerouted. Does this happen in any other place in the browser? For instance, if the fallback is an edit control and the user drag-selects some text on the canvas, is it expected that this text is also selected in the edit control?
