Microsoft has been updating their Windows 10 software with some features that are new to the scene. One of those is the Task View functionality that has been added to the task bar, which has an icon that looks like this:
Once you click on the icon, it will give you a list of recent items you have worked on, items you are currently working on, as well as suggestion tips for Windows 10 that you might want to check out. Clicking any of the items opens up that item, or switches to the item, if it is currently open.
Check out this video to learn more: