NB 4.1 (200505031930)

The uniqueness of the event handler in the whole class (not only among the
handlers for actual event) is checked after closing the handlers dialog. If some
duplications are found the handler is deleted form the handlers-list.

Steps:

1) create form with some componet 
2) select this componet and switch to the events in the property list
3) click to the ... in the first event 
4) add handler1 and handler2 methods
5) close the dialog
-> the two methods are created, two handlers are listed in combobox of the
appropriate event

6) select the 2nd event from the list and click on ...
7) add handler2 
-> the name isn't unique but it isn't checked at this moment

8) click ok

-> the "handler is in use" warning is shown and the handler isn't added.