@LTT. I had already tried your first suggestion but it didn’t work, I guess because it conflicts with the normal string I had defined for [. Your suggested regular expression didn’t work either until I also defined a regular expression for the normal bracket ^\[. So now I have a regular expression of ^\[- for disabled key and ^\[ for enabled key and everything works fine. Just offering this detailed explanation in case someone else runs into the same issue. Thanks again.