Double Click-Throughs


When I started thinking about this topic about a week ago, it was originally going to be a rant about NetNewsWire and how its click-through behavior was so frustrating. Upon doing a little research however, I discovered this problem is not specific to NNW, but all OS X applications, and I’m certainly not the first person to talk about it (John Gruber has a number of interesting reads). I have stumbled upon something however that I’ve been unable to find mentioned elsewhere online, and that’s the inconsistency between single and double click-throughs in an application.

First, a definition from the Apple Human Interface Guidelines to make sure we’re all on the same page, and not talking about banner ads

An item that provides click-through is one that a user can activate on an inactive window with one click, instead of clicking first to make the window active and then clicking the item.

Often, click-through is discussed in terms of whether or not an inactive application “receives” the click. Developers have the choice of making click-through active on most any object within an application, and there are various schools of thought on what should and should not allow click-throughs. I’m more interested however in “double click-throughs”, or whether an application receives a “double click” message when it is inactive.

An illustration

As I’ve already mentioned, this all begin with an annoyance I discovered in NetNewsWire; here’s my basic workflow

  • browse through headlines in NNW
  • open full article text in Safari
  • after reading article, close Safari window and click back to NNW

This works okay, unless in clicking back to NNW I want to select something other than what is currently selected. For example, if I currently have as my selected feed, and I click on my Slashdot feed with NNW being inactive, then all that happens is that NNW becomes the active window. I must then click once again to actually select the Slashdot feed – this is completely expected behavior when click-throughs are turned off. What is not expected however, is that if I perform this second click too quickly, then NNW receives a double-click action and opens the Slashdot homepage in my browser. The problem is that NNW does not allow single click-throughs but it does allow double click-throughs. The only way to make a new selection in NNW while it is inactive is to click once to make it active, pause for a moment, and then make your actual selection. Talk about annoying!

I realize I’m kind of picking on NetNewsWire, but that’s only because this is where I first noticed the issue. Apple applications are no exception - this inconsistency in click-throughs can also be found in iChat’s Buddy List window and Mail message listings (though I’m sure there are many others). iTunes’ track window seems to behave consistently however – neither single or double click-throughs are registered – so apparently it is possible.

The Remedy

I’m certainly not a skilled interface designer, so I’m not about to jump into the debate (religious war?) of when click-throughs should and should not be allowed. I am however quite skilled at the role of “end-user” and can recognize inconsistency when I see it. I’ve only toyed in Interface Builder quite briefly, so I don’t know if it has different properties for single and double click throughs. If not, I would suggest some mechanism for consistency be added, and if it’s already there then I would suggest to developers to use the same value for both.

Comments and responses

The behavior you’re seeing is the standard Cocoa behavior. There are no settings in Interface Builder for how this works – the way it works is the way it works.

I highly recommend reporting it as a bug to Apple. (But use their apps as examples, so they won’t think it’s a NetNewsWire bug.)

You do need to be an ADC member – but, if you’re not a member already, you can become one for free.