How do I color the background of a row over the complete width like www.coffeecup.com. Now it stops to early, see www.qtouch.nl.

Select the row > then in design panel set max-width None. and background color your desire color

My row is width None, my Grid is max width 1200, if I change that to None, all my rows are stretched. That's not what I want. I am doing something wrong.

See if these two demo helps ( Watch at fullscreen HD View )
https://youtu.be/VzSbMs1jB5w
or
https://youtu.be/zzjylGEi088

Ok, I do understand that, but what's then the best way to create the left and right margin for the content?
Columns?

If the row does not have a max-width, the columns will keep stretching. To center content you can, for example, use a single column in that row and then drop in a subgrid (or container). You can give the subgrid the same max-width as the other rows and center it by activating the margin-left/right auto check boxes.

The settings are in this screenshot and attached the rsd project I put together (real quick):

So, I have been working on it all evening. Everything changed to subgrid, lot of work, but worthwile. Thank you for your help.