I need to match a single quote that only follows a comma. I don't know much about regular expressions but from what I've read that would be a 'look behind' expression written like this:

(?>=,)"

I get the message "can't find the word" when I search for that (I do have "regular expressions" box checked.) I thought there might be a problem with the characters, so I tried searching for (?>=a)b because I know that should match the first line. It should find a "b" that follows an "a" but only select the "b". That isn't working either. Am I doing something wrong, or is this 'look behind' expression not supported in Notepad++?