DoubleClickjacking: A New type of web hacking technique

I’ve tried to explain it many times too, but I can’t really articulate a good, comprehensive rule for when to single and when to double click.

Another complicating factor that many less-tech-literate don't have a good internal model for is window focus. I've seen several people try and single-click on a not focused web button, only for nothing to happen. When they click again, the button is activated. They then learn to always double click that button.

Having a mental model of "this button needs to be double clicked" gets them the result they want, even if that's not a very accurate reflection of the computer.

When you're on windows and not in the browser, you double-click to launch a file or program in the Explorer (which also is what runs the desktop). Single-click is select.

So, the rule:

List of files on your computer or desktop? Double-click. Otherwise? Don't.

What if I’m opening an email in Outlook? What if I’m looking at something in Control Panel? (That one’s a trick question, since the answer has changed in modern Windows versions.)

In theory: if you’re clicking on a UI element that has some notion of being selected, then a single-click selects it, and you need a double-click to take an action on it. If there’s no notion of selection, then a single click takes an action.

In practice: adherence to this ranges from perfect to abysmal. And users who don’t understand the computer well may not know how to think about whether a given UI element is selectable or not.

I'd say don't do that. Who reads emails?

Although seriously, I find I never break out of the preview in Outlook email. The only spot in Outlook where I really need to double-click is the calendar. Which is annoying.