Undesired behaviors after upgrading to new Mac

I've been using on e iMac since 2014 and last summer bought a Mac Mini for other use. I tried BTT on the Mini at that time and it worked without problems - at least none I remember. (I just copied the directory in Application Support and all the settings copied over.) I ran into some other issues with my overall setup and decided to migrate my main workstation to the Mac Mini. I wiped it clean and started copying things. I did not use Migration Assistant for multiple reasons. I did reinstall BTT on the new setup on the Mini and copy over the settings from my old iMac in the Application Support folder. I'm using an Apple trackpad instead of a mouse.

Things seemed to work until I tried a game that allows me to use some swipes or to select areas of the playfield by using two fingers on my trackpad. Instead of doing what would normally happen, I'm getting a red line that is drawn by my movements. If I remember, from experiments long ago, that's from trying to use gestures with BTT. I've looked through the parts I understand (on both BTT and Apple's Settings), but I can't find anything specific that I can tell is causing the problem.

What did I somehow activate or what is going on with this that is causing it?

Not a solution, but additional information. Any two fingered swipe brings up Launchpad. I've never used Launchpad, so I didn't realize just what it was. I've looked in my Settings and can't find anything there that uses a 2 fingered swipe other than going to the next or previous page. Same in BTT prefs. But pushing down and swiping 2 fingers horizontally or vertically brings up Launchpad. Just resting 2 fingers on the touch pad and swiping doesn't do it.

Had to transfer everything to another computer. I copied all my BTT settings from my old system, but I'm running into this again.

It's odd - I make a habit of going back and documenting how I fix issues like this, but I seemed to have forgotten to in this case.

Correcting my last response: I also found it's a click-two-finger-swipe, not just a simple two-fingered-swipe. So any click-two-finger-swipe brings up the dark rectangle and starts drawing a red line. Doing this as a down-swipe brings up launch pad. I don't have anything set in Apple's settings to do this.

sounds like you have BTT‘s „drawings/mouse gestures“ enabled and also enable right-mouse drawing. You can disable this in the BTT settings

Yep, that was it. I kept looking under "Touchpad" and not "Gestures." That was it. Thank you!