I have a similar problem described here: Microsoft Wireless Display: black border around image (screen image is scaled down)
However, I'm casting from an Android phone (the native casting called Smart View) to a Windows 10 PC. In fulscreen on the PC I can read the phone, but when I resize it the borders show up and make impossible to see. Android cast has an option named fullscreen on connected device, but activating it does not solve the issue. See the screenshot. Any help?
