Wacom Intuos Pro - holding option for clone stamp/healing brush wont work

It works fine when holding option and clicking on the part I want to source with the clone stamp tool when I use a mouse or track pad, but when I ust the wacom tablet the little circle with the crosshairs in it disappears the moment the pen gets close to the tablet. So I can't use the tool with the tablet because it won't let me click on a source spot. Any ideas why this is happening? I've updated to photoshop 2017, have the newest driver for the tablet. I'm on a 2011 mac, still running yosemite. The tablet is brand new.