I have a X201 ThinkPad Tablet in which all the pen functions stopped working (that is: Eraser, side button, tap and hold for rightclick Etc) beside the very basic function of writing on the screen. Touch functions seems to work fine, though.
I tried installing various drivers from Lenovo and Wacom with no luck, so I thought it might be a hardware problem, maybe a pen battary (is there one?)
Recommend uninstalling ALL wacom/pen/touch drivers, then try installing the drivers from lenovo's End-of-life Products Archive for your computer. The pen does not use a battery, and it sounds like a software problem since writing on the screen works and tap/hold for right click does not.
Here are some citations for those who may be interested in learning more about the pen and sensing technology....
http://en.wikipedia.org/wiki/Wacom#Technology "Wacom tablets use a patented electromagnetic resonance technology. Since the tablet provides power to the pen through resonant coupling, no battery or cord is required for the pointing device. As a result, there are no batteries inside the pen (or the accompanying puck), which makes them slimmer."
http://www.gottabemobile.com/2011/07/10/n-trig-vs-wacom-a-dual-digitizer-duel/ "Finally, all the current N-Trig tablets are using battery-powered pens. This adds a bit of weight to the pen, but not much, and I preferred the heft over the feather-light Wacom pens. The AAAA battery supposedly lasts for thousands of hours, and though uncommon, it is a standard size. I spotted it at Rite-Aid and CVS, so no need to special order one when it runs out. N-Trig does make a digitizer that can work with a battery-free pen, but vendors don’t seem to be going for that. Wacom pens are always battery-free and last for years."
Lenovo never used N-Trig in their tablet PCs, only wacom, which never used batteries in their pens.
Here's an announcement from the X41 tablet, Lenovo's first of this series: http://forums.tabletpctalk.com/viewtopic.php?t=2094 "Wacom, the leading pen tablet manufacturer, announced today that its Penabled(R) cordless, battery-free pen technology has been selected for the Lenovo ThinkPad X41 Tablet - the first convertible Tablet PC from the ThinkPad portfolio. "