It took me a while to get this right.
When a VM has usb.vbluetooth.startConnected= TRUE, then mouse wheel will always be triggered to the left.
Host is Ubuntu 18.10 with multiple kernel tested from 4.15 to 4.20. With multiple DE.
This happens on Windows 10 and 7.
Using the tool QiPress to display mouse events I caught the issue.
I also tried on a Ubuntu 18.10 and evtest to watch the events and the issue does not happen.
This is a hard to notice issue as most applications does not care for horizontal scrolling/mouse wheel.
I just notice on some specific place on Lightroom which uses it for zoom.
Changing usb.vbluetooth.startConnected to "FALSE" works around the issue, but will probably make bluetooth unusable.
Can more people confirm this issue?
-rsd