A while back, I made a virtual machine on VirtualBox for Android 4.4. I had a little trouble getting mouse integration to work for it, but I figured it out.
More recently, I tried Android 6.0 Marshmallow on a virtual machine. Mouse integration would not work, and as such, I could not get as far as setup. I've since moved back to Android 4.4 which displays a mouse pointer just fine.
Does android-x86 6.0 not support mouse integration?