taken from Tablet Forum Review
Active Pen stylus support on Windows 10 (64bit) for Dell Venue 11 Pro 7140
I never really managed to incorporate the use of Active Pen in my use of the 7140, so most of the time the stylus would end up depleted in a drawer. This particular stylus uses (rare) AAAA (4xA) batteries so I try to remember to remove them before storing my stylus away.
Occasionally I do want to scribble or draw on the tablet and I've noticed that windows 10 wouldn't detect the stylus. Often the battery is just depleted but lately I've noticed that I need to reinstall the drivers to get the stylus to work.
I can't find the drivers in Dell website but luckily someone posted it in TabletForumReview (link above).