The reason is that the left_file is contained in the template and in all templates and pages.
So if you clicked Update in step 4, you create a process stream that updates those files. All format*templates were created from the template. If you clicked Update in step 4, a second process stream would be created when the template was updated with the change to the left_file in order to update all the file that use this template.
Just note that any referenced files still need to be added to the project folder.
In the October 2014 release of Photoshop and Illustrator CC, a new feature called (see Figure 1) are a powerful feature that lets you create, categorize, share, and store your favorite colors, brushes, text styles, graphics, and vector images in one easily accessible place.
That Library content can be accessed on any machine or mobile app that supports Libraries, as long as you log in with the same Adobe ID.
and when I go to edit the template and library files in Dreamweaver, they do not update their child-pages. I went back into my other drive (that I had initially made the website in), and updated something on the template page, and a thing pops up and goes through the process of updating each of the child pages. Does anyone have any idea what is going on with copying the files to another drive, that makes it not update?
Updating the original file will not update the files in other drives unless you are using some kind of version control, you will have to update all the copied files manually.