If the parentheses are not closed in the regular expression, Expresison constructor can't devide Trigger Expression correctly.

Steps to reproduce:

1. Create the following Expression.

   find(/Zabbix server/logrt[/var/log/^test.log$],,"regexp","(aaaa)")=1 and find(/Zabbix server/logrt[/var/log/^test.log$],,"regexp","(bbbb")=1 and find(/Zabbix server/logrt[/var/log/^test.log$],,"regexp","(cccc)")=1

1. Click on Expression constructor.

Result:
Expression constructor divided into Expression A and B.

Expected:
Expression constructor divided into Expression A and B and C.