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From: norman@sdcsla.UUCP (Donald A. Norman)
Newsgroups: net.cog-eng
Subject: Re: default menu item selection
Message-ID: <778@sdcsla.UUCP>
Date: Thu, 31-Jan-85 08:44:46 EST
Article-I.D.: sdcsla.778
Posted: Thu Jan 31 08:44:46 1985
Date-Received: Sun, 3-Feb-85 05:44:23 EST
References: <722@ihuxa.UUCP>
Reply-To: norman@sdcsla.UUCP (Donald A. Norman)
Organization: U.C. San Diego, Cognitive Science Lab
Lines: 34
Keywords: mouse pop-up menu spatial consistency
Summary: 

In article <722@ihuxa.UUCP> steffen@ihuxa.UUCP (Joe Steffen) writes:
>When you press a mouse button to pop-up a menu, should the top item be the
>default selection, or the last item you selected on the menu?  The latter
>has the advantage that clicking the menu button repeats the last operation,

An important principle, but one little remarked upon, is that of spatial
consistency.  Spatial information is a very important and powerful cue for
remembering things.  It is important not to violate this principle.   A
pop-up menu that reogranizes itself with each usage violates this principle.
(I am almost tempted to say that it violates human decency, but that, of
course, would be flaming.)

There is a second alternative, followed by some Xerox PARC pop-up menus:
the ordering of the menus stays the same, but the initial mouse position
(i.e., the highlighted item on the menu) initially appears on the last item
selected with that menu.   Even here, I am not sure whether this violates
the principle, because even though the ordering of items on the menu
remains constant, the relative movement of the mouse to pick an item
changes from usage to usage.  An experiment is in order.

An alternative that appears to combine the best of all features (except
perhaps adding some confusion on first experience) is for the inital mouse
pisition always to be on the menu header (a non-item), but that the
highlighted item initially be the last item selected.   Then, a click gives
the previously selected item.  To make a new selection, move the
mouse to the position:  any movement into the menu region cancels the
initial default.   In this case, both ordering of the menu items and
relative motions of the mouse remain constant for each use.

 Donald A. Norman
 Institute for Cognitive Science C-015
 University of California, San Diego
 La Jolla, California 92093
 UNIX: {ucbvax,decvax}!sdcsvax!sdcsla!norman   OR   ARPA: norman@nprdc