Is it possible to configure Fibaro Dimmer 2 with double push button (Legrand 664508 in this case) so S1 acts as a dimmer and S2 is used to for example activate scene?
What you describe is mentioned in post 4 and 6 in this thread: https://community.openhab.org/t/fibaro-fgd212-dimmer-2-dimmer-channels/38200/4 and further some explanation in this thread: https://community.openhab.org/t/question-regarding-fibaro-dimmer-2-fgd212/13488/2