I am very happy with my ThinkPad Yoga S1 with Windows 8.1, and like very much the digitizer pen capability. It works well (given some calibration issues) when the Yoga works without an external display.
However, as soon as an external display is connected (I"m using OneLink Pro to connect), the pen outputs always on the external display and not the internal (the yoga screen itself).
I’ve attempted to set the yoga screen as the main screen, but did not have success. Also using DVI instead of display port did not help. I also tried it with three displays (internal, DVI, DP) all in the extended mode (it is nice that these setup as possible by the way), but the pen still it appears on the display port monitor.
In order to use the pen meaningfully, I have to disconnect all external monitors and work only with the yoga screen.
There is no such issue under Linux though.
Anybody has seen this? Is this an issue of the pen driver (all updated to the latest state) or the operating system (Windows 8.1, 64bit)?