How to customize the do-Organizer Navigator
You are not restricted to do-Organizer Navigator defaults. The ability to change folder icons and text styles to your preferences are available.
Customization options are applied item-by-item not to all items globally. To customize any selected Navigator item, select the item "Properties" command from the navigator right-click menu then you will see the "Folder Item Properties" dialog below.

There are two tabs in the Folder properties window:
1. Details tab page: Here you'll find typical item property details such as Item name, created by, created on, item-type, comments and Flag Markers. An additional attribute you will not see on an ordinary property dialog is the "Flag Marker". In addition to visual customization you can assign a flag marker to your selected folder.
2. Display tab page: This is where you make most of the visual changes. On this tab page you can change Text Color and Style and the Item's Icon.
Tick the "Use customized font style and color" check box and select your custom font, style and color. On the screen capture above I have used a quite large font with green color for the purposes of this guide. However, I wouldn't use 20 point fonts for the navigator in real life as it would look disturbingly large for my tastes.

On the other hand, for some, it may be a better way to work. It's all about providing choices and leaving the decisions to the user.
At the bottom part select the "Use custom icon" radio button then click on "Choose from Icon Library" if you want to change the default folder icon.
After all the changes are carried out, remember to click on the "Save" button.
The following capture from the sample database (contacts navigator) shows the customization of font style, color and icon:

Default folder icons are replaced with The Country flags. The USA folder text color and style are customized but the font-face is kept the same.