Can not install more than on SimpleDataField on F3

On my fenix 3 i can't install more than one SimpleDataField i developed myself.

If I copy more than one to the device, I only can select one. The device deletes the second prg-File by itself.

This problem may be caused by the naming of the class SimpleDataField.

The class that extends App.AppBase must be named SimpleDataField:

class SimpleDataField extends App.AppBase


Otherwise the prg is not running (on the simulator).
I have seen samples, where the class is not named SimpleDataField, but I couldn't get them running.