I think it would be super useful to have an OnFocus event that triggers, like when someone starts editing text for example. It would probably have to be on focus enter and on focus exit, but I could see it being super useful.
It would be nice to have an OnFocusEnter and an OnFocusLeave event so we could have a way to render a control differently when the user has the focus on it restore it to its normal state when it leaves the control.
I'm a bit surprised this doesn't already exist. OnFocus and LostFocus would be HUGE. I'm really struggling with an app because this functionality isn't available. I hope this is considered soon.