I can't add add a link to a newly uploaded document to selected text in the new RCE. In the old RCE you can select some text and add a link to a newly added document without changing the text.
In the new RCE when you select text, and add a link to a new document that you upload from your computer, the text you've selected will be replaced with the filename of the new document.
Adding internal links to pages was one of the killer features in the old RCE. It was very easy to connect course content without leaving the editor area.
I suggest that this mistake should be rectified.