Formatting properties available through DocumentBuilder are like “formatting at cursor”. That is, if you move the cursor into a certain place, formatting properties of DocumentBuilder will take on the formatting available at that location. Also, if you set color and start adding cells, you will be “moving the cursor” with every insertion and they will all come out in the same color until you change it.
In your case, you simply need to set color and fill options before creating every cell or set it (switch off) after you created the first cell.