How can the color background be changed?

For the current document, you can change the background color by:

1. Choose Edit > Colors… to bring up the color picker 
2. Select a color that you desire 
3. Drag from the box at the top (or the boxes at the bottom) into the Cartographica window 
4. When the color swatch drags into the Cartographica Map area, the area will get a drop border and you can drop the color into the map and the background color will change

To change the background color for all future documents:

1. Choose Cartographica > Preferences… to bring up the Preferences window 
2. Click on the swatch next to Default Map Background Color to bring up the Color Picker 
3. Choose your new color with the color picker

From this point forward, all new documents will use the new background color.