How to detect that focus is in a filtering header

I have a grid, I set a filtering header

$mygrid.setHeader("x, y, ..."); $mygrid.setColTypes("coro,edtxt, ...");

How can I know that focus has moved there (or that the user has begun typing something in one of the cells) ? I want to detect this in an unintrusive fashion. I have no problem with the current filtering logic, I don’t want to rewrite it, I just want to know where the focus has gone.

No way to do this ?

Please, try to use teh onFilterStart event: … event.html