Hi Nancy,
I understand what you are saying but I had already detached the template so there was no longer any template in use and except for one section with script tags, there are no errors that could not be easily cleaned up by editing the code. It is now a "standalone" page and I should simply be able to edit it, comment portions out, correct spelling problems, etc. Why would this capability be removed from a program in which it used to exist?
Just frustrated that something so simple would no longer be part of a program I've been using for well over a decade. A menu option could be added that that allows users to edit the code, regardless of whether it is a template, child page, etc.
I addressed today's problem using Jon's suggestion, and created a new page with the same name, copying all of the code that came before the one small section mentioning CSS styles, then copying everything after that section, that was blocking me from being able to edit the code.
Will keep using DW CC but for older sites will use some other program from now on. The program may be great for developers, but for minor changes, it's just too much of a learning curve and and too bulky for simple page modifications. I didn't create the pages I'm working on, but took on the weekly maintenance, so this is what I have to work around.
Thanks to you and Jon for your help today, I really appreciate it. 
Lynn
Please show us the code you're trying to work with.
I suspect the so-called detached file is not fully detached from a template. Or possibly you had been using a nested template which further complicates matters. Until that's resolved, you'll need to open the file in another plain text editor that doesn't recognize Templates like Notepad, Brackets or Text Wrangler to fix the code problems.
Nancy