Touchscreen problem with Ubuntu mate in Toshiba Ultrabook Z20t

Hi, I have installed Mate 16.04 in my 2in 1 and works great, Touch screen work ok in normal laptop mode. I need to run the tablet part in Portrate mode but the touch curser is all wrong, if I leave the screen attached to the laptop and turn the whole thing on it’s side and connect a usb mouse, it works correctly.
I need to use it as a tablet in Portrate mode to display pdf’s as big as the screen ( Sheet music) which it does very well but I also need the touch function to work as well.
Any suggestions, please