Unfortunately, Samsung only recently started allowing third party applications to access the S Pen side button while the S Pen is touching the screen. Prior to the Galaxy Note 4, the side button could only be detected while the S Pen is hovering above the screen.
Samsung devices we know allow the S Pen side button in Squid are:
- Galaxy Note 4
- Galaxy Note 5
- Galaxy Note Edge
- Galaxy Note Pro 12.2 (with Android 5.0 Lollipop update)
- Galaxy Note 10.1 2014 Edition (with Android 5.1 Lollipop update)
- Galaxy Tab A 9.7" with S Pen
We hope Samsung continues to allow access to the S Pen side button in their future devices, and older devices through software updates!