In previous Act! versions the Activity info from the Regarding Line used to display on the forefront of the calendar.
Now Act! will display the contacts names that are involved in the activity rather than the regarding line. Only when the contact does not have the activity scheduled with another individual is the regarding line shown on the calendar.
In the preferences of the calendar you have the ability to view the contact's name or company's name, but not the regarding line. I feel this would be an easy addition to the software that would offer great valuable.