I have the same problem on an X220T, whose screen can flip into a tablet mode. The touchscreen works great for everything until I want to type something. In Gnome Shell, anytime I select a text field with the touchscreen, it assumes I want to use the on-screen keyboard (OSK) and automatically pops it up. If I begin to type on a physical keyboard, it gets rid of the OSK and lets me get on with life. It seems to me that this may be a good approach here as well! Definitely would work better than the MS way of doing it, always having to press a button to make the keyboard appear.
I have the same problem on an X220T, whose screen can flip into a tablet mode. The touchscreen works great for everything until I want to type something. In Gnome Shell, anytime I select a text field with the touchscreen, it assumes I want to use the on-screen keyboard (OSK) and automatically pops it up. If I begin to type on a physical keyboard, it gets rid of the OSK and lets me get on with life. It seems to me that this may be a good approach here as well! Definitely would work better than the MS way of doing it, always having to press a button to make the keyboard appear.