Enterprise Architect enables you to highlight particular message flows in a Communication diagram using different colors for each message set.

To highlight the colors in a Communication diagram, follow the steps below:

1. Select the Tools | Options | Communication Colors menu option. The Communication Message Coloring page of the Options dialog displays.
2. Select the Use Communication Colorcheckbox.
3. Click on the drop-down arrow of each Message n field, and select the required color for each message group.
4. Click on the Close button. On your Communication diagram, each sequence group of messages displays in a different color as shown below.