okay, I think I have figured it out.
Since this tablet has a FHD screen in 10.6", I turned up the text zoom to 150%. Zooming to 150% causes fuzzy text and the cursor shooting off screen issue.
Going back to 125% zoom, which is the default, text becomes sharp and cursor behaves correctly.
I tried it with SDL and GDI and both behave the same way when screen is zoomed to 150%.