Other problem:
in one window in explorer.
When I change the view, e.g. from large icon to details. the focus jumps to the address bar and it drops down the history.
It should be noted, that in order to see this issue, the focus must first be in the address bar (e.g. navigate to a folder by typing in the address bar). Then the issue occurs when selecting any item from the View menu or Sort menu.
One workaround is to select any item from the ⋯ menu, such as Select none. That will set the focus to the main window.
It's mind boggling that Microsoft could fix this issue when using the New menu, but completely overlook View and Sort. It's also mind boggling that simply clicking in the main window does not set the focus to the main window.
P.S. While testing, Explorer got stuck into a display problem where both the address bar and ribbon became blank. I had to restart Explorer (or sign out and back in) to fix it. I've seen this issue many times and thought it was a display driver problem with my VM, but I'm now thinking it may be another bug with the App SDK version of Explorer. Have you seen this issue?