"light" skin causes background image to repeat

I have a grid using the ‘light’ skin:


If the user shrinks the columns (causing text to wrap), the background image “repeats”, causing a weird look (see image)

Is there any way to fix this so the background is a constant gradient that doesn’t repeat?

Unfortunately it is not clear what skin do you have.
The “light” skin doesn’t look like the the grid on your screenshot.
Please, make sure that you are not using any custom created skin or you didn’t modify the “light” skin.