Shift + Scroll on normal mouse

Describe the bug
When I hold down Shift for horizontal scrolling, it doesn't work.
When I disable BTT, it works again.

Affected input device (e.g. MacBook Trackpad, Magic Mouse/Trackpad, Touch Bar, etc.):
Logitech M570

BetterTouchTool Version: 3.553
Mac OS 10.15.7

I have the same issue. I use Steermouse because it's the only driver I've found that offers chording and allows different settings for different mice. If I disable either that or BTT then Shift scroll works again as expected. So there is obviously something between these two programs.

If BTT did chording for mouse buttons then I could live without Steermouse, this would be the ideal for me!

Coming here to say the same thing. Just installed SteerMouse and all horizontal scrolling is ignored with both BTT and SteerMouse are running. In my case, it was just the shift key that was being ignored.

With BTT running and setting the horizontal scroll on a Command key modifier SteerMouse was able to pass through.

Even without any mouse events being captured in BTT (I deleted all of them), of which I had some in both FinalCut and Sketch apps, SteerMouse was being preempted by BTT.

Quit BTT and SteerMouse works, run BTT and horizontal scrolling with shift stops. I agree that something is going on between the two apps.

My solution was to disable BTT for the dedicated apps where I prefer SteerMouse. The solution is here.

The downside is losing mouse support in all BTT for the sake of horizontal scrolling via SteerMouse? Further testing needed.