Ubuntu 18.04 multitouch

Hi,

I'm trying to make multitouch work on my Yoga 720 touchable screen.
- Zoom in / out in libre office or PDF viewer works (is it related ?)
- Pressing multiple areas on screen don't (but was working in 17.10)
- I use Bitwig and SunVox to test (musical softwares with virtual piano keyboard and other multitouchable controllers)
- When I press an area it works. If I press two areas at the same time It does not work. If I press one areas and another one while keeping the first one pressed, the first one works and the second one dont or trigger the sound of the first one (do not know if I am understandable ;-) )

xinput --list

Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ Wacom HID 50F1 Finger touch id=12 [slave pointer (2)]
⎜ ↳ MSFT0001:02 06CB:7F8F Touchpad id=10 [slave pointer (2)]
⎜ ↳ Wacom HID 50F1 Pen stylus id=11 [slave pointer (2)]
⎜ ↳ Wacom HID 50F1 Pen eraser id=15 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
    ↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
    ↳ Power Button id=6 [slave keyboard (3)]
    ↳ Video Bus id=7 [slave keyboard (3)]
    ↳ Power Button id=8 [slave keyboard (3)]
    ↳ EasyCamera: EasyCamera id=9 [slave keyboard (3)]
    ↳ Ideapad extra buttons id=13 [slave keyboard (3)]
    ↳ AT Translated Set 2 keyboard id=14 [slave keyboard (3)]

xinput --test 12

motion a[0]=8021 a[1]=5619 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button press 1 a[0]=8021 a[1]=5619 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button release 1
motion a[0]=8523 a[1]=5587 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button press 1 a[0]=8523 a[1]=5587 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button release 1
motion a[0]=8405 a[1]=4306 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button press 1 a[0]=8405 a[1]=4306 a[2]=0 a[3]=0 a[4]=0 a[5]=0
motion a[0]=8399 a[1]=4313 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button release 1
motion a[0]=7432 a[1]=5321 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button press 1 a[0]=7432 a[1]=5321 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button release 1
motion a[0]=7500 a[1]=5522 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button press 1 a[0]=7500 a[1]=5522 a[2]=0 a[3]=0 a[4]=0 a[5]=0
button release 1
# keep one finger pressed and press another area
button press 3
button release 3

Is it supposed to work ? Is it an ubuntu issue ? Is it a client software issue (bitwig / sunvox) ?

Thanks