from
The Free On-line Dictionary of Computing (8 July 2008)
context-sensitive menu
<operating system> A {menu} which appears in response to a
user action (typically a {mouse} click) and whose contents are
determined by which {application window} was clicked or has
the {input focus}.
Most {GUIs} use a secondary mouse button (right or middle) to
call up a context-sensitive menu as the {primary mouse button}
is normally used to interact with objects which are already
visible.
The context-sensitive menu often contains functions that are
also available in a {menu bar} but the context-sensitive menu
provides quick access to a subset of functions that are
particularly relevant to the window area clicked on.
The {RISC OS} {WIMP} uses only context-sensitive menus (always
invoked using the middle mouse button). This saves screen
space and reduces mouse movement compared to a {menu bar}.
(1999-09-22)