Has this turned into a history lesson in old editors?
Speaking of the SAS program editor, why would you want the enter key to split the line when you just trying to get to the next line? The big problem with the "enhanced editor" or EG or SAS/Studio over DMS editor is that it is not really part of SAS. You can not use SAS code to create command macros for them. I have command macro to generate a macro call from the source of any autocall macro. Or insert the list of variables from a SAS dataset.
WYLBUR was a wonderful program editor. I am convinced that the CHANGE command could not only slice bread but toast it and put the butter on. I even found a PC version I could run on my IBM 5150.
For the office Christmas party in 1979 someone at my office programmed the ROSCOE editor to run TIC-TAC-TOE including randomly deleting one of the lines in the file it used to pick its moves so it was possible for the kids to sometimes win.
Do you still remember what key on the VT-100 keypad was the Insert Line function in the EDT editor?