We've had quite a few complaints about a problem with scheduling appointments and auto-completion. I've seen the problem but I've been unable to reproduce it consistently enough to file a good bug report.
The problem occurs when you're scheduling an appointment and you go to the schedule view tab and start typing an attendee name in the open attendee text input. Sometimes when auto-complete has selected a match for what you've typed and you hit return to select it, the name will auto-complete but the interface fails to create the next attendee slot and move down to the next text input as it normally does. You can't enter any further attendees in schedule view until you switch to one of the other tabs and then back. If you switch to appointment details the attendee who was just selected does not appear the attendee list.
I haven't been able to find any particular pattern in the contact entries or appointment details. The same entry will trigger the problem in one case and not in others. When the problem occurs I can repeat it two three times and then the problem seems to go away and it's not repeatable.
Has anyone else encountered this problem. We're running 5.0.6 and typically we're seeing this on Firefox 2 or 3 under Windows and Linux.