You can mark a TMail Pin with a Star. This Star indicates that the corresponding TMail is marked as important.

Stars are an alternative to Trackers to mark TMails as important. However because Trackers are part of the Message Flow they have the additional semantic of whether you expect to act on them, wait for something etc.

In Navigation, select a folder to see the target list of TMail Pins. In the list, the header row shows the names of different columns such as Star, Subject, and Type. (To customize the list view for what all columns you can show or hide for this specific list, please see Global Tasks for details.)

See the Star column in the list, as below.

Click on the Star on a TMail Pin to mark it as important as shown below.

The Star marked TMail Pins gives you an option to find one or more specific TMails quickly. You can assign Priority to these TMails to sort these by Priority. (Please see Assign Priority to TMails, for more details.)