The value in the 'Trigger status' drop-down list in Monitoring -> Triggers is not being stored in the users profile and as such is not being remembered if the user leaves and returns to this page.

This feature was implemented before but disappeared in r13042.
The commit message points to https://support.zabbix.com/browse/ZBXNEXT-424
r13042 | vedmak | 2010-06-22 14:48:04 +0200 (Tue, 22 Jun 2010) | 2 lines
ZBXNEXT-424 enhanced status of trigger filter (Vedmak) - merged: branches/1.8 13041

I have attached a patch to fix this issue in r33785.

Special thanks to Volker for his help.