I recently updated my computer to Windows 10 build 10122 and have since had an issue with Minecraft. My screen has black edges around it. I've tried reinstalling, downgrading (version 1.0.0 alpha works without black edges), reinstalling Java, using the .exe and .msi. None of these work. I also reached out to Mojang support but received no help. The game works perfectly fine in full screen though. The issue seems to be in windowed mode only. I've seen the issue in 1.7+.