Do not show all fields at once, but start in the sensor screen and switch to the pushbutton screen after loading if needed.
implements #16512
@chhitz at first I tried not to show anything and unhide the fields once data was loaded, but that turned out to be quite complicated due to a bug in the spinner field user extention. This second version is indeed as simple as you expected it to be ;) The dialog will always start with the sensor fields and will switch to the pushbutton fields after loading if needed, I hope that's enough.