Don't know about the DX200 but usually in Android to enable developer mode you do this;
Open Settings> About> Software Information> More.
Then tap “Build number” seven times to enable Developer options. ...
Go back to Settings menu and now you'll be able to see “Developer options” there.
Open Settings> About> Software Information> More.
Then tap “Build number” seven times to enable Developer options. ...
Go back to Settings menu and now you'll be able to see “Developer options” there.