Horizontal scrolling is the ability of a program to allow a user to scroll horizontally using the window scroll bar. The horizontal scroll bar is not used often and usually not visible or not accessible because it is not needed. Below is an image of a Microsoft Windows window with a vertical and horizontal scroll bar.
When you copy a file to the desktop you are putting the actual file on the desktop whereas when you put a short cut on the desktop you are just placing a reference to where the file is actually located.