Hello Tobias,
thank you very much for the quick reply. I have tried intensively your suggestions.
But still I am not able to store presets for the widget using the “sandwich” icon on the top right corner of my module.
darktable.preferences.register and darktable.preferences.write are working both fine for my code. If I register the preference I can easily manipulate it from the built-in perferences dialog under the section “lua options”. But I cannot store it as preset.
For the second button in the top right corner I successfully use the “reset_callback” of the widget that I add using darktable.register_lib. But there is no “store-presets_callback”.
Any further ideas?