Ian McCollum, who runs the Forgotten Weapons YouTube channel has published another film a few days ago, in which there is another Polish gun presented. The video is about a pocket-sized one-handed SIG Chylewski pistol. It was a weapon made by the Swiss SIG company, in which the idea of a Polish engineer named Witold Chylewski from Lwów was used. He filed a patent for a"Self-loading gun with a movable auxiliary trigger for moving back the slide" (Patent No. 306 from 1924) in the newly founded Polish Patent Office (created in 1919, the year Poland regained independence). It is worth noting that inż. Chylewski developed his solution several years earlier - where Poland was still partitioned. In 1914 he filed two patent applications at the Austrian office and obtained relevant patents in 1914 and 1915.

The video from the Forgotten Weapons channel:

More information about the SIG Chylewski pistol and later designs using a "movable auxiliary trigger" can be read in one of the Minionek's entries: http://rozkminyminionka.blogspot.com