@dawnlis Hi. thank you for trying out Pencil2D. Regarding the Surface Pro, unfortunately it’s been a while that this has been requested but the best sort of response I can muster right now is that “it is supported but we don’t know how it works yet”.
Apparently it should work with the latest versions of the technology that Pencil2D uses to build itself (Qt framework) however since we don’t have custom code for it to work with Windows Ink (software like Krita does), that’s why it doesn’t work out of the box with a surface pro. The new version of Qt should address that but the building platforms haven’t yet been upgraded for that, so we have to wait for a conclusive solution or that someone merciful enough wants to help the project by coding support for that like the one that did with Krita.
Sorry that I can’t be of more help but the human resources we have are simply not enough to pursue such endeavors without relegating vital fixes of the software. With that said please try to use the latest development builds from time to time to test out if there are advances in that regard: http://pencil2d.org/download#nightlybuild