We are hamstrung by old code here. ```AdminEditPage::init()``` foolishly calls ```$this->ui->init()``` already, after initInternal().

I don't see how we can handle that more gracefully without either rewriting ```AdminEditPage``` and dealing with lots of fallout in old code, adding a new method to run after initInternal() and the ui inits, or sticking with what we have here.

We can still modify the ui in subclassed ```initInternal()``` before it's loaded, which is all we've ever used in the admin before.