As countless interface designers and usability experts keep pointing out, consistency in your application is a key method of improving user friendliness and overall usability: Establish one way of doing something, and then stick to that throughout your application. This way, your customers get used to how your application works and reacts, usability and productivity goes up, and everyone’s smiling.
One of the key strengths of Apple’s design in the past was the overall attention to consistency and a particular attention to the little details. Mac OS X is still leagues beyond any other operating system available in the design and consistency department, but with every release of Mac OS X teeny gaps have started to appear in Apple’s, er, armor. Okay, that metaphor is rather weak, but I’m still working on my first coffee of the day, so cut me some slack…
Here’s a perfect example, as found in Apple’s Mail:
When I control+click on my Junk mail folder and select “Delete Junk Mail”, I get a dialog asking for confirmation:
But if I do the same and empty Mail’s trash, I get a sheet instead of a dialog:
According to Apple’s Human Interface Guidelines:
“A sheet is document modal—that is while it is open the user is prevented from doing anything else in the window, or document, until the dialog is dismissed. In contrast, a dialog that is application modal prevents the user from doing anything else within the application.”
In this case, both the sheet and the dialog prevent usage of the application, as the sheet is attached to the main Mail window and not a separate document window. So why the inconsistency?
I totally agree that this is nitpicking, but in my opinion it’s little inconsistencies like this that add up. It’s reasonably easy to nail consistency for the bigger things (like the overall look and feel of an application), but, as the saying goes, god is in the details.
I’d love to find out if this inconsistency is a bug, or if it’s done on purpose, and if so, why.