I recently purchased an XPS 15 9550 and I need middle mouse click in some of my applications. Under touchpad settings, It only allows mapping 3-finger click to Cortana or Activity Center. Does anyone know how I can get the touchpad to send a middle mouse click to my applications?  On previous laptops I have owned, they typically included a Synaptics touchpad, which always made it easy to perform this mapping using a 3-finger click, but it seems like Dell has included something custom and no such options appear to be available. Any help would be appreciated.