Comment 31 for bug 859474

I'm also effected by this and it is not restricted to unity or gnome. I am having the same problem in xfce.

As has been explained by Alti El at https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/874675 , the action to drag seems to have gone from (Tap)+(Press) to (Tap)+(Press and Drag)

The frustration is then initiating the drag on the second touch before the timeout. Increasing the timeout certainly makes it more possible, but there are many times when I would previously pause, whilst pressing my finger, before I'd initiate dragging. I now have to arbitrarily move to initiate the drag before the timeout before I can pause to work carefully.

There's no reason the action should require the drag to be initiated before a timeout. A double click can be represented by a double tap, so as long as the finger is removed on the second tap before a timeout it will register as a double click, and if the finger isn't removed before the timeout it registers as a drag.