Palm Treo 300 - Manual (Page 116)

Section 6
108 Application-Specific Tasks
Preferences
ᮣ Remember last category. Determines how the Contacts
list appears when you return to it from another
application. If you select this check box, the Contacts list
shows the last category you selected. If you clear it, the
Contacts list displays the All category.
ᮣ List By. Determines how the Contact entries are sorted in
the Contacts view, and also controls the PhoneBook
Instant Lookup feature.