Re: [Usability] Re: Keyboard navigation- outstanding issues

[George <jirka 5z com>]

On Mon, Oct 01, 2001 at 01:37:22PM +0100, Michael Rogers wrote:
> Perhaps there should be no default button in such cases, for two reasons:
> 
> (1) The 'only one obvious way' principle, as above.
> (2) In most dialogs, <Enter> closes the dialog and performs the action. If 
> in a few cases it closes the dialog *without* performing the action, the 
> users may incorrectly assume that the action has been performed. This is 
> particularly serious when the action is dangerous.

I agree with this.  If we go with the proposed Enter semantics, I think that
none of the "dangerous" dialogs should have Enter perform the action.  Tabbing
over and pressing space or perhaps Alt-O for OK would be much harder to do by
mistake.

Now I'm thinking of a time a long time ago when we had a piece of lab equipment
(at time of gtk1.0) controlled by a gtk program.  In a lab you make use of the
keyboard a LOT, but these are also people that normally use a mouse, so they
get easily confused.  I suppose such people would be the perfect test cases, as
that way you figure out if the keybindings make sense to a person who is not
used to using them.  Anyway,  In the program we sometimes had a dialog pop up.
I think one of the cases was in the middle of a sequence it would pop up a
dialog if soemthign was low or whatnot, and if the person wanted to stop the
thing or go on (in which case the machine assumes the person has done the
action required).  Now what happened is that there was default and focus.  But
these people would tab over to the right button and press enter.  And then
they'd get on our back about the program being broken (of course you have to go
watch them do it to finally figure out what they are doing, because they say: I
pressed Cancel, and it continued.  Or something to that effect.)  At that time
I implemented the gtk+ patch to do the moving defaults (by doing exactly what
motif does).  I suppose making no default is also a gooD way to do this.

In any case, my point is, that we need to be VERY careful with Enter as it's
quite often pressed by mistake.  If it can cause damage or be more then a
little annoying, then Enter should probably not do anything.  As in the case
above, people don't learn semantics of the program if they don't notice
what's going wrong.  And even then they continue to do such errors if it's
simple to make them.

George