In Panels you have the option to create three columns and then disable the blocks on the left and right. When one does that one expects the three columns to cover also the area that used to be taken by the blocks. This does not alwauys happen so and that seems to be theme dependent.

In my case the three columns stay confined to the main column on the left side, the rest remains unused. How can I make these 3 columns cover my whole page.

Many thanks

Theo Richel