For example, trigger expression very simple:

{Template_APC_Automatic_Transfer_Switch:icmpping.last(0)}

#1
We can look some events on Monitoring->Events page.
After trigger expression will be modified to

{Template_APC_Automatic_Transfer_Switch:icmpping.last(0)}

#1&

{Template_APC_Automatic_Transfer_Switch:icmpping.last(0)}

#1
Press F5 on opened Monitoring->Events page, now we can not look events! Triggerid was changed!