Accepting/Declining an appointment in the opened invitation mail not possible

Concern:

Accepting/Declining an appointment in the opened invitation mail is not possible in
Outlook and clicking on the corresponding buttons has no effect.

Solution:

Currently appointments can only be accepted or declined if the user accepts
the appointment from the e-mail list and doesn't open the invitation e-mail.

Update:

Issue has been fixed in Outlook OXtender versions bigger than 6.10.1 .