Yes, in my experience, the Anytone AT-779UV and the Radioddity DB20-G are interchangeable both as radios and programming software.
Try changing, in the Model Information -> Model menu from 136-174/400-490 to 136-174/400-470, and see if that solves your problems.
And power off, hold down V/M button, power on and what firmware version (for example at the bottom: V2.26) do you have?
Are you also double clicking the >> at the end of each Channel listing to open up a box for Tones, etc.?