V10/man/man9/mouse.9

.TH MOUSE 9.4
.CT 1 comm_term
.SH NAME
mouse \- jerq mouse user interface
.SH DESCRIPTION
Most jerq programs use the mouse for control, either by pointing at things
on the screen or by making selections from a menu.
The mouse buttons are different from keys on a keyboard in that
events are reported when a button is released (let `up') as well as
depressed (pressed `down').
It therefore matters not only
.I where
and
.I when
a button is pressed, but for how long.
For example, menus are drawn when a button is depressed, and remain
displayed as long as the button is held down.
While the button is down, moving the cursor over the menu highlights
entries in the menu; the entry (possibly none) under the
cursor when the button is
.I released
is the selection returned to the program.
Large menus also present a
`scroll bar'
on the left side of the menu.
Moving the mouse inside the scroll bar chooses which subset of the
available entries are displayed and therefore selectable.
.PP
There is a convention about how the buttons are used.
The left button (button 1) is used to point:
selecting which layer to work in, which file inside the editor,
some text in the file, etc.
The middle button (button 2) produces
a menu of actions related to the selection:
remove the selected text, replace it, etc.
The right button (button 3) presents a menu of global, program-wide actions:
pick up a new file, rearrange the files on the screen, etc.
Programs follow this convention well enough that an unfamiliar program
can often be learned simply by trying it.
The main violators of the convention are drawing programs,
which use button 1 to draw things and button 2 to undraw them,
but this is also a consistent convention.
.PP
The mouse cursor is usually an arrow pointing at a pixel, but
programs often change the cursor to an iconic representation
of the program's state.
The most common cursors are:
.TP
arrow
standard cursor
.TP
coffee cup
Program will be busy for a while.
.TP
rectangle and arrow
Program expects a rectangle to be `swept out' by pressing
a button (usually 3) at one corner and releasing at the diagonally opposite corner.
.TP
gunsight
Program expects an object to be selected by pointing at it and pressing a button (usually 3).
.TP
upside-down mouse
Program is thinking; the mouse is inoperative.