How can see latest operational data in Problem dashboard

[bab]

I know we can see latest operational data in dashboard but I have create a trigger with follow info :
Name: service error
Event name : service error : {ITEM.LASTVALUE}
Now trigger fire when expression is more than 0 and it shows service error:1 but when chnages to 2 it does not show service error=2 in problem dashboard . What should I do know ? I want to see this change in problem dashboard