I have searched high and low but never found something like this, so I have to ask!
When I edit an HTML or CSS file (say index.html) I usually try to take advantage of other people's ideas (I am a perpetual newbie-amateur), so I also open someone else's index.html to get ideas from (read copy-paste!).
Now I have two index.html files side by side and must take care NOT to inadvertently change the "other" file (that I'm copying from). Most editors allow you to show the full pathname to each file but for good reasons this is not always the best solution.
Things get worse when I edit several HTML and CSS files...
A good solution would be to be able to drag the "read-only" tabs to the right and leave the "working" tabs on the left side.
Is there an editor that can be configured this way?