Athena Scrollbars: Why people love them

Many applications, e.g. xterm, xman, xdvi, ghostview and xrn use the Athena widget set.

The Athena widget set is favoured by many users because of its highly functional scrollbars. Unfortunately, many more users have not noticed the benefits of this interface even after using it for many years. So here's a short introduction (for vertical scrollbars and right-handed mice; I assume you are smart enough to figure out the other cases if you need them):

The middle mouse button
is known by most: When you press it in the scrollbar, it moves the scrollbar such that its top is where the mouse points. Dragging up and down moves the scrollbar accordingly. The content of the window moves proportionally to the scrollbar movement. This is the usual stuff.
The left mouse button
When you left-click in the scrollbar, the content of the window that is at the height of the mouse moves to the top of the window. So, if you want some line to move to the top, you move the pointer in the scrollbar right beside the line and press the left mouse button; if you want to scroll a windowfull downwards, you move the pointer to the bottom of the scrollbar and press the left mouse button; for half a window, you do it in the middle; and for only a tiny bit, you do it near the top.
The right mouse button
scrolls up as much as a left-click scrolls down. E.g., for scrolling up a full screenful, you right-click at the bottom of the scrollbar. To undo an overeager scrolldown you just right-click at the same place (and vice versa). Unfortunately there is no direct visual way to scroll a particular line down to the bottom.
The main benefits are that you can scroll the exact amount that you want (at least downwards) and that you can switch scrolling direction without moving the mouse (which, among other things, makes it easy to undo a scroll).

GNU Emacs apparently does not use the Athena widgets, but has implemented Athena functionality in its scrollbars (the first and sufficient reason why I prefer it over Xemacs).

Related links

Anton Ertl