User defined regular expression test function return incorrect result with "Case sensitive" option and "Return is TRUE or FALSE" expression type.
"Case sensitive" option returns the opposite result.

Expression: crit|error|fatal|alert|emerg|panic

1.
Case sensitive: false
Test string: crit
Result: TRUE

2.
Case sensitive: false
Test string: Crit
Result: FALSE

3.
Case sensitive: true
Test string: crit
Result: TRUE

4.
Case sensitive: true
Test string: Crit
Result: TRUE