How to Add or Remove a Color Filter to a Panel

To add a color overlay to a panel:

Click on the Color Pallette icon below the panel.
Choose the color filter you'd like.

At the bottom of the panel you should see four icons: Sun, Moon, Clock and Color Palette. Click on the Coloring Palette icon to see the coloring filter options. Now you should see the color filter options. Select one to apply it to your panel. To remove the color filter, click on the first option with the circle and a line across.