3 Button Mouse Emulation? Could Be Causing Problems

I have an iMac and an Apple Touchpad. Haven't had problems before now with anything and being able to use BTT to add a few things has been a major help.

Now I'm using Blender for 3D modeling and, in one case, the Alt button is not working as it should. According to Blender people in forums, the issue, in the past, as been an issue with 3 button mouse emulation. I don't have that option on in Blender, but I'm told that you can get 3 button mouse emulation in the OS (on some systems, maybe Linux?), or by other programs on the input chain.

I'm in the Trackpad section of BTT's configuration panel, but can't find anything about 3 button mouse emulation.

Is it possible I have, somewhere in BTT, picked an option that is either actual 3 button mouse emulation, or that does the same thing?