One of the changes in Windows 10 is that all Modern apps run inside a window. This makes them appear similar to classic desktop apps - now they are resizable, have a titlebar, icons on the taskbar and window caption buttons. However, since Modern apps are primarily touch-optimized, some users might prefer to run them full screen always, like they used to run in Windows 8 by default. This is very easy to do.
- Open some modern app.
- Take a look at the titlebar. Next to the app's icon, you will find three little dots.
Click those dots.
- A special menu will appear with the commands that used to be present as Charms. Select Fullscreen there and the app will go fullscreen.
- To exit fullscreen, you need to move your mouse pointer to the top edge of the screen. The titlebar will popup, there you will find a similar button with dots: