Adding Colors to Identify Messages by Topic
Postbox allows you to set custom colors for each Topic, so which have been assigned a Topic stand out in the message list. Here's how:
Assign Colors to Topics
To assign a color to a topic, go to Postbox > Preferences > Display > Topics. Then, select a Topic, and click the edit button at the bottom of the list (pencil icon). Finally, click the colored box next to the Topic Name, and choose a color.
Apply Color to the Entire Row
If you'd like the color to apply to the entire row (and change the color of the subject, sender, etc.), check the box (in Postbox > Preferences > Display > Topics) that reads: Apply the topic color to the entire row in the message list pane.