Would event.currentTarget be correct? If so lose the "variable for nothing" headerTag and/or the use of the outer variable inside the function handler.

Seems like a lot of work though since you still have to dispatch the event, meaning why not just make it a normal function and skip all the rest of that?

Though it could be fun to set that up with defineProperty and a get/set, so the setter triggers the update. I might play with that later… would get you spitting distance from making “views”.