I'm having the same issues. Since the last two builds on my Surface Pro 4. I can use the start menu to scroll to the app and click on it. The problem is with the Cortana window. I got used to typing the first few letters of an app which then brings the app up so I can click on it. When I do that now, the app appears but the screen is unresponsive. I cannot click on anything within the window that opens which looks very different than it used to.