Many of the UI elements do not behave correctly when using the Microsoft Surface pen. When clicking a file with the pen it is interpreted as 2 separate clicks and opens the file twice. Many buttons interpret a tap with the pen differently from a tap with a finger. For a lot of UI elements, the pen does nothing at all. In that case, I need to call up the on-screen touchpad emulator. It really ruins the point of using a tablet with a pen.