Second delection of booking does not work

Description of problem:

If there are two or more bookings already done and you try to delete one after another, the second deletion fails.

Version-Release number of selected component (if applicable):

WFK2 ER8
EAP6 CR1
FF 10.0.3 or Google Chrome 17.0

How reproducible:

Always.

Steps to Reproduce:
1. package and deploy Ticket Monster example
2. create at least two bookings
3. click on Bookings menu item
4. click on 'tray' icon to delete one booking
5. click on 'tray' icon to delete another booking

Actual results:

Nothing happens, the deletion of booking is not triggered.

Expected results:

The booking should be deleted.