Ubuntu – Fully disable “tap and drag gesture” for synaptics touchpad

I recently got a new Dell XPS 15 9550, and I followed the instructions of the OP in this thread https://ubuntuforums.org/showthread.php?t=2317843 to set it up to dual boot Windows 10 and Ubuntu 16.04. (Basically just disable safe boot and fast boot, change from RAID to AHCI in BIOS, then install Ubuntu and make sure graphics and other drivers work). Everything works pretty well immediately after installation.

I want to disable the "TapAndDragGesture" which is enabled by default in synaptics. But when I use synclient to do so: synclient TapAndDragGesture=0 the gesture does not completely go away. The behavior is that now, if I double tap, it will drag for a brief period of time (about half a second, as opposed to dragging for however long I keep my finger on the touchpad).

This is still very irritating as the amount of time it drags is still enough for me to accidentally move tabs around (as I tend to do when quickly tapping to switch tabs).

Has anyone experienced this issue or something similar? And does anyone know how to fix it? Thanks in advance.