How does the win10 system fix folders to the taskbar?

Specific methods:
1, in the "Recycle Bin" or any other folder, here we created a folder named "ldquo; fixed to the taskbar!". Right-click and select “Fix to "Start”Screen";

2, then click the Start button and you can see that our folder has been added to the start screen on the right It is. Then right click on it again, select “fix to the taskbar 

3, then come back and see, is not the folder that could not be fixed to the taskbar, has been fixed on it Now?

4, but at this time, in the start screen, there are still folders we just added. Let's delete it, click the Start button again, find the folder just right, then right click on it and select “From “Start”Screen Unpin “. Well, to start screen does not show, but it is still fixed on the taskbar! (Refer to the actual effect of the second picture)