Looking for beta testers to try app's redesign

[Qbert]

After doing a check on some clean OS Versions, the mouse buttons behave different using
OSX 10.11 (El Captain) witch I'm using and on MacOS 10.12 (Sierra).

On MacOS 10.13 (High Sierra) both buttons work the same.

Probably Apple changed something in their mouse drivers.

[(cool) Hector]

Thank you for the clarification! El Capitan is quite old, so I won't bother with that issue.