I just upgraded to the latest RStudio, R 3.4.4 and all my packages are up to date too. My machine is running ubuntu 18.04.2. I use a small Wacom Intuos pen and tablet as a disability aid instead of a mouse or trackpad; up till now this has worked fine with everything I've tried, without an added driver (this is good, because the driver is sometimes a pain). I don't have a special driver for it right now.
Since the RStudio upgrade, the tablet is working fine with all the menus and some of the buttons (Knit, for example, is absolutely fine, as are Save and Publish). However, some are not! Settings, Run and most infuriatingly Insert are completely ignoring the tablet, though they respond to the trackpad. I have tried the usual closing and re-opening and rebooting, to no avail. This makes no sense to me. I know this is a bit niche, but has anyone else seen this and found a fix?