It just that I cannot run FrontPage at the same time - inconvenience
And I would call this a blessing!!! If you are going to use Zen Cart and/or other scripts much...wean youself away from Front Page. It generates bloated code and MS has dropped it as there are many security issues with a FP site.

I know that it may seem like a comfortable old friend that you do not want to scrap....

Get a good straight text code editor, one that has color coding and will inform you of incorrect code by color. Or notepad will suffice in a pinch. These straight text editors do not add any additional and unwanted stuff to your edits.