Connected the Surface 3 to the Microsoft Wireless display adapter, which uses Miracast, and discovered that it displays at a very low resolution (1366 x 768) on my HP EliteDisplay S240ml. Found out that others are having the problem, and turns out to be some type of conflict with Bluetooth. Turn bluetooth off and I can then get 1920 x 1080 display. #

According to the support thread, the issue has to do with the latest Intel video driver for the Surface that for some reason is dropping resolution down to 1366 x 768 whenever it detects a bluetooth device other than the Surface Pen is connected. #

The solution is to either turn bluetooth off or not use any devices other than the Surface Pen. #

I can report that any time I connect a bluetooth device, or even turn it on or off, the wireless display disconnects. What this means to me is that for now I cannot use the Logitech k480 keyboard with the Surface if I want to connect the Surface to my monitor via the wireless adapter. #

My workaround is to use the Logitech mouse and keyboard that connects via a USB dongle with the Surface. The result is that I have keyboard, video, and mouse all wireless attached to the Surface even if to do so requires a little work on my part to plug in the USB dongle. #

An interesting side note. If you turn off bluetooth you can still use the Surface Pen with the Surface. I imagine bluetooth only needs to be on for the initial pairing. UPDATE: I discovered that the top button on the Pen uses bluetooth. If bluetooth is turned of the top button on the Pen does not work.#

One more issue, there doesn't appear to be a fast way to make the Miracast connection from the Surface. The Windows key+P combination to project does not provide an option for wireless display; It should. The fastest approach is to go to the Start Screen and start typing wireless, which will bring up a search box of all wireless items on the Surface, including connect to wireless display. #