Hi Richard,
Notepad++ is capable of opening many document types, from File in Notepad++ open the folder containing the source files you're interested in then open the scrit files that are associated with the scripts(s) you are working with.
If there is a particular text (e.g. variable name) you are interested in, double click on it in an opened script to view which files it occurs in. For example this will help to view where the function / variable etc occurs. I found this approach helpful to gather my wits on "what was going on" in the code.
Please do let me know if you have any more questions.
Wish you good results!