This is the follow-up task for the task "Create an About dialog for the coordinate grid plugin". It's highly recommended to complete the about dialog task before starting this one.

The coordinate grid should receive a configuration dialog where the user can edit the color for the normal coordinate grid lines and for the tropical/arctic circles and the equator.

The configuration dialog would show three buttons (shown as "[ ]" below ) which have the background color for the lines:

Color

[ ]  Normal Coordinate lines

[ ]  Tropical/Arctic circles

[ ]  Equator

Have a look at

http://techbase.kde.org/Projects/Marble/OnlineServices

and at the existing Online Plugins. The Wikipedia plugin has got a configuration dialog  that you can use as a "template".