No Invite button on the Attendees properties sheet due to standalone mode.
Cause:
Schedule+ is running in standalone mode. The 'Invite' button is only available in group-enabled mode.
Solution:
Exit and restart Schedule+ and choose 'Group-enabled mode'.
1) Select the 'File' and select 'Exit' to close Schedule+.
2) Restart Schedule+.
3) Click 'Yes, work in group-enabled mode' radio button when the Group Enabling dialog box appears.
Work in group enabled mode dialog box
4) Click 'OK'.
