How do I hide the interface when drawing in Version 6?

Just updated from ArtRage3 to ArtRage6 - How do I hide the interface when drawing in Version 6?

I am used to hiding the interface when drawing, called "Clear Canvas Mode" in version 3, then showing the interface again to change tools.
In version 3 I just right-clicked the screen to toggle Clear Canvas Mode on and off... but in version 6 right-click brings up a context menu with no clear canvas mode option.

so.... how do I hide the interface when drawing in Version 6?

Appreciate your help