There are severe practical difficulties in applying these properties to the "hex" display. Any change in either "side" of the display needs to be carried forward to the other side, so the task is quite challenging. So, for now, lets settle on making the "ordinary" display capable of editing and the changes saved, but make it impossible to do that when the file is opened in "hex".
First we add a new menu item entry for the "Save" option. Just go to the "Menu Editor" and insert the new entry. I have placed it before the "Exit" option.
I shall develop the other changes in two parts:
My suggested coding is stored in "TextView4.prj" and hence in "TextView4.exw".
Now move on to Stage 5.