Open your Carbonite Options window (type "/carb options" in chat, right click the Carbonite minimap button and choose "Options" in the menu, right click a non-icon area of any Carbonite map and choose "Options" in the menu) and go to the "Map Minimap" page. The option you want is one of the last four at the bottom of that page.
Open your Carbonite Options window (type "/carb options" in chat, right click the Carbonite minimap button and choose "Options" in the menu, right click a non-icon area of any Carbonite map and choose "Options" in the menu) and go to the "Map Minimap" page. The option you want is one of the last four at the bottom of that page.