Unable to change program name in EV3 IDE
I believe this only happens when there is already a program with the same name.

If you start a new project and add 3 new programs named 1-1, 1-2 and 1-3, it works as expected. But if you try to add a 4th program named 1-1, 1-2 or 1-3, then the name will revert back to the default name because there is already another program with the same name.