Copyright 2004 by M. Uli Kusterer Fri, 29 Nov -1901 11:06:32 GMT Comments on article blog-consistency-and-uniqueness at blog-consistency-and-uniqueness Comments witness_dot_of_dot_teachtext_at_gmx_dot_net (M. Uli Kusterer) witness_dot_of_dot_teachtext_at_gmx_dot_net (M. Uli Kusterer) en-us Comment 1 by
Thanks! :-)

"However, I do not think that custom controls should be used very often."

Neither do I. I am usually more of a "Usability Nazi", freaking out over every UI element that isn't "the way it's supposed to be". I assumed that most people reading my blog know this and thus look at the post from the perspective of someone who usually would *never* dare even suggest that consistency has its limits.

"And if you've ever seen someone double-click a "delete" icon in a window toolbar, making them inadvertently delete two list items and not noticing it, you'll know that this isn't necessarily harmless."

Well, that particular example is based on a misunderstanding, however: double-clicking an item always meant "perform the default (most plausible) action on this". It never meant "treat this like a button". The system tray in Windows, in theory, is a good example of this (in practice, it's a horrible one, since almost no system tray icon behaves like another): single-clicking a tray icon shows up a menu with one of the menu items in bold. Double-clicking a tray icon performs the action the bold menu item would have performed. (So much for the theory, anyway.)

The whole confusion over single- versus double-clicking goes all the way back to one Mark Andreessen who hated double-clicks and believed there should never be a need for them. The application whose interface he was working on, thus, did not use double-clicks and instead performed its most important action with a single-click. That application was Netscape, and because of it, all modern browsers click a link with a *single* click, in total contrast of behaviour elsewhere in the UI. (The only browser I can think of that supposedly -- I never had the pleasure of being able to use it myself -- did it properly was "the original", World Wide Web, for NeXT. A single click would *select* a link, allowing you to do something with it.)

"I still have people asking me whether they should single-click or double-click, simply because there's no clear rule anymore now that a single click launches an item in the dock and the dock - as opposed to, say, the launcher - uses icons instead of buttons."

Absolutely. Unfortunately, we will likely not get out of this mess any more. This is why it's so crucial to avoid UI design mistakes to begin with: once they spread, you will never get back, because some people have already gotten used to going about things the wrong way.