Multiple Power Sources

So before I try this I'm wondering if anyone else has. My monitor for my 12" rMB has a USB-C input, which works much better on this new Pro (Actually supports 60hz 4k and scaled resolutions.) It also supplies power, but apparently not enough to charge this new laptop. In fact, not even enough to hold charge, as my battery is slowly draining.

My question is, does the laptop choose only one port to charge from if there are multiple potential charging sources? As it seems I am going to have to plug in the included power cord for the time being until I find a better solution (Probably a dock with integrated power passthrough.) I'm thinking it does, but I'm flying out in a day from now and don't want to accidentally fry my new laptop before the trip (When I get back, maybe )

 

Ok, that is what I thought as far as multiple power sources. The monitor I have is the LG 27UD88-W, interestingly that page does say that it supports charging laptops up to 60w. I'll have to try it again tomorrow. It was plugged in to the right side ports, but I don't think that should matter...maybe there is a some monitor config setting I have to change.