Can't search case-insensitive with (?-i)

[VaelVictus]

(?-i)vaely gives the error: There is an invalid character in a target pattern.

Is this not the best way to search for a case-insensitive term?

[ghost]

Ordinarily it would be (?i) to make it case insensitive (and (?-i) only if you need to make it case sensitive again partway through)

Unfortunately the regex parser this program uses doesn't seem to support it.

Best workaround I've found is to do like [Yy][Ss][Aa] for case-insensitive ysa