My bad. I should have stated the original search like this, I suppose:
Find what box: (?-s)^(?=.*def)(?=.*phone).+
Match case checkbox: unticked or ticked <------ as you need
Not everyone knows that:
leading off your regex with a variant of (?i) will search case INSENSITIVELY (the i is for Insensitive) leading off your regex with a variant of (?-i) will search case SENSITIVELY (the -i is for NOT [or “minus”] Insensive)and that these little strings, if used, override the setting of the Match case checkbox, since they are logically processed after the checkbox setting.
However, the misunderstanding could have been avoided had some sample data been provided along with the original question.