can´t change column width

I try to modify the column width in template settings "Layouts". I.e. I change the left column width from 20% to 15%, but nothing happens. All changes in template columns shows no effect. I use a fresh installed yourShop-Template, Joomla 2.5.6 with virtuemart 2.0.8e.

A short hint would be great!

Hi,
did you clear cache after you change it ?

Thanx for quick reply. Yes, I did.
Fond the fault. I used GK4 in the columns. This modules overrides the CSS of the template. It works after changing the thumbnail-width in GK4.