To pin a window to the side of the screen, you simply drag it by its title bar until the mouse cursor hits the left or right boundary of the screen. Before you let go of the mouse button, you will see a ghost of how the window will be placed. Let go of the mouse button and the window will drop there. Pull the window off the side of the screen, and it will automatically undock.
If you use two monitors, however, you cannot drag the window to the inside edge of either monitor to make the window attach at the middle boundaries - not very helpful.
But, you CAN do this. All you have to do is use the Windows Key Shortcuts on the keyboard to make this work. Win+Right and Win+Left will put the window through all of the available positions, including the edges between the two screens. Perfect.
Please check out the video to see this in action