One coloumn instead of two in theme Twenty-ten

In theme twenty-ten it is possible to have one coloumn instead of two (optional). I have a testsite and a normal site with the same theme. In the top bar, I point at “Edit page” and one of the choises are to select “one or two coloumns”. When I do exactly the same on my normal page, I do not get the same choise! I have tried for 2 hours without luck.

How do I go from 2 columns to 1 coloumn on the front page in theme twenty-ten? My page is: https://www.abhbyhus-ollioules.dk