Trigger for regexp from snmp traps

[highland]

Hello

I've configured host Default_Trapper with Item snmptraps (type Zabbix trapper). Traps are received correctly. For example in Latest Data for this Host i have:

10.200.12.10 / 10.200.12.10 :: Normal :: linkUp - Link FastEthernet0/31 UP. Admin state: up. Operational state: up.
10.200.12.10 / 10.200.12.10 :: Normal :: linkDown - Link FastEthernet0/31 DOWN. Admin state: up. Operational state: down.

I want trigger which looks (regexp) for string in this item. So i've created trigger named Trigger_interface_down with such rule:
Default_Trapper:snmptraps.regexp("linkDown")}=1
Then i created Action which have condiction as:
Trigger = "Default_Trapper:Trigger_interface_down"
and operation send email.

After receiving trap trigger worked, and i received event but:
in the Action column for that event there was no action (and i did not receive email).
Moreover after receiving few such traps (linkDown) in the event there was always only one event for that. Why ?
How can make trigger makes event wvery time i receive trap ? And why action do not appear ?

EDIT: i've noticed that this trigger in fact do not work, because event is generated on any trap !
It does not matter if i have trigger:
Default_Trapper:snmptraps.regexp("linkDown")}=1
Default_Trapper:snmptraps.regexp(linkDown)}=1
Default_Trapper:snmptraps.str("linkDown")}=1
Default_Trapper:snmptraps.str(linkDown)}=1.
It always make an event for trap:

10.200.12.10 / 10.200.12.10 :: Normal :: linkUp - Link FastEthernet0/8 UP. Admin state: up. Operational state: up

Why ?
Some of my event have status problem, some of them have status OK, can i control it ?

How can i clear all events ?

@nelsonab - i'm becoming enthusiastic about zabbix