I ordered a pen interface device for my PC (Huion 420), excited to be able to handwrite/draw notes on PDFs, in addition to typing notes on them. However, when I have the device plugged in, the free drawing tool stops working. I can click with the mouse or try to draw with the pen/pad device. Nothing shows up. The drawing tool does, however, work with my mouse when I unplug the device. This bug is one of the main features preventing me from using Adobe Acrobat as my primary note-taking software in medical school.