Matrix report 4th row group subtotal row color

I'm dealing w/ SSRS 2005.

I have my main matrix report which has five row groups.

What I'd like to do is have the subtotal at the 4th level have a coloring for the whole row at run-time...so the user can follow from left to right what the 4th level subtotal actually is (the report can get fairly wide).

At design time, you don't even see the rows to the right of the subtotal, you just see the subtotal box.

Thanks!

got it...click on the little green triangle in the upper right corner, and set the background property.