This issue has been in since day one of Windows 10 Edition, but I've never bothered to report it until now...

When system performance gets low, or a lot of things are happening within Minecraft, and you start clicking, for some reason the mouse will drag itself out of Minecraft Windows 10 Edition. Which will then freeze your input. Or at least the mouse input, most of the time. Then you have to click back onto the window to regain input. It can sometimes effect keyboard input too. A lot of the time, it doesn't visually happen, unless it's really intense on performance.

I don't imagine it would happen on Gaming PC's, because they're powerful, but mine isn't.