Question often asked to me.
The solution is simple :
Helpers Standard Grid Check Autogrid radio box in the parameters of the Helper Object Grid Create the grid on the surface you want to be align on Right Click the viewport Activate Grid On the left top part of the viewport, Left Click on the actual name of the viewport Click on Extended Viewport Grid Top
Tadddaaaa !
When editing is finished, delete the grid...
I hope it will help users
Trick tested and appouved on Max 2018, Max 2017.