I know this may be an old topic, but I just noticed it as I now have a new 13" 2016 MacBook Pro w/ Touchbar. Having come from a MacBook Air where 3-finger drag was far and away my most common gesture I have been very frustrated that the operation on the the MBP was inconsistent. So I just spend an hour with Apple Support. The answer: "The feature was only intended for and designed for moving windows around. It as never intended for use within a window to do something like select text." This was according to what seemed like level 3 support - the people who back up the people who answer the phone. The person pointed me to the following article:
https://support.apple.com/en-us/HT204609
Bottom line - According to Mike at Apple Support, the capability so many of us enjoyed on our MacBook Airs for the past few years was not supposed to work that way. So, if you are on the latest firmware and sofware (which I am: Sierra 10.12.2 and firmware 1039) and have all the correct options set such as Tap To Click, etc. (which I do according to the Apple support people) and it didn't really fix anything. It still doesn't work consistently. This functionality was available on my prior system (MacBook Air). I am screwed. There is no fix coming. There is no answer. According to Apple, the way so many of us have been using it was never supposed to work that way and I have no recourse. (Even though it was an Apple store employee who showed me how it worked to select text, draw objects, etc. on my MacBook Air.)
I know this is an old topic but I want to be sure that people know what they are getting if they buy one of these MacBook Pros. Had I known, I would not have purchased it. And since Apple strung me along with non-solutions to the problem I am passed the 14-day window and unable to return this MacBook Pro to get my money back so I can revert to my older MacBook Air which worked the way I liked.
