Option to toggle Lock zoom X+Y track view.

[John Paul Anthony Dela Cruz]

Hello guys. I would like to propose a lock toggle feature that would allow users to zoom out the track view X axis & Y axis at the same time.  

Currently I bleieve you can only zoom out axis separately through hotkeys or buttons. This would be helpful in cases where users would like to have a better control zooming in or zooming out inside the track view UI.

Thanks.