[Usability] panel usability

[Boris Goldowsky <boris alum mit edu>]

Hi all.

Our Linux machine has recently become the primary computer for our 
family (switching from Mac OS X), so we've been running a bit of a 
usability test case.
Basically, everyone's been happy with the transition, so many thanks and 
congratualtions are in order for making gnome a very friendly and usable 
environment!  In the hopes of making it better, though, this message 
concentrates on the problems encontered...
It turns out the biggest confusion has been the transition from Mac OSX 
dock to Gnome panel.
[For those not familiar with it, the Mac's "dock" has an icon for each 
currently-running or commonly-used application (you can drag & drop them 
there), so it is like a combination of the panel launchers and the 
window list.  Clicking on an icon brings the program to the front, 
starting it if it is not currently running but otherwise simply 
un-hiding and fronting its windows.]
Usability issues with the panel have been the following:

- clicking on panel launchers for currently-running programs, hoping to 
bring them forward.  In many cases, this starts a new instance of the 
program instead.  Some, like Mozilla and epiphany, have internal logic 
to just open a new window rather than start a new instance of the 
program.  Most simpler programs, however, do not, so you get an extra 
Gnucash, or Print Manager, etc.
- double-clicking a launcher is the same, only twice as bad.  You get 
TWO instances of a program attempting to start at the same time.  That's 
slow, and for programs without a clear startup notification, often an 
impatient user will try clicking again to fix things.  Then (early in 
this transition) they would come and ask me why nothing's working.  By 
the time I got there, there would be half a dozen Mozilla windows 
stacked up.
- The mail notification applet requires a double click if you want to 
use it for starting your email application.  Also desktop and nautilus 
icons require double-clicks.  Sticky notes does not behave like the 
launchers; it toggles.  I can see arguments for all these behaviors, but 
collectively they caused quite a bit of confusion at first.
My conclusions? 

1. It would be very nice if everything on the panel would be 
"de-bounced", and treat a double click as equivalent to a single click, 
unless some other behavior is explicitly configured.  In no case should 
a double click open two new windows or two new programs -- the habit of 
double-clicking to launch things is just too well established.  If you 
really wanted two new windows, you would give two clicks with some time 
in between.
2. All launchers should just tell the application to open a new window, 
rather then starting a new instance of the program. If the program 
cannot do that (eg, Gnucash), then the launcher should just make the 
existing windows visible.  Starting another instance of an app, while 
there may be use cases that require it, as far as I can see would be of 
interest only to relatively experienced users, and so could be accessed 
through a menu or a configuration option of the launcher.
3. Startup notifications are critical.  I'm happy to see them starting 
to become more common.
Sorry if some of this is old hat -- I'm just hoping to provide some 
useful data on what confused a couple of new users.  Feel free to draw 
your own conclusions from it.
Boris