Single-click or double-click? (10/22/08)

The very short answer
If you're not sure whether to single-click or double-click, trying clicking once and wait a few seconds (wait longer if you're on a web page or using the internet in some other way). If that doesn't do what you want, then try double-clicking.

However, sometimes double-clicking is a waste of effort, and other times it may get you into trouble.

The more in-depth answer
In the real world, you probably know that pressing an elevator button more than once is a waste of time, but when you knock on a door you probably knock two or more times. With computers, ideally you could simply tell by looking whether the item you want to click should be clicked once or twice to get the result you want. Unfortunately, it's not that simple.

Are you a chronic double-clicker?
Has this happened to you? You single-click on, say, a document icon and wait for it to open. While it probably becomes selected, nothing else happens. So, you double-click on it and then you get what you wanted. This confusing or frustrating experience has probably happened often enough that, like many other computer users, you developed the habit to double-click almost everything. It's understandable, and probably works most of the time, but it might occasionally cause problems. Why? Because if you double-click on an item that only expects to be single-clicked, you can't be sure what the computer will do with that second click:

Will it be ignored?
Will it be treated as a second single-click on that same item?
Will it perform that "left-over" single-click on another item entirely?

What's a single-click? What's it for?
A "single-click" is a tap-and-release on the left button on your mouse (or, if you're on a Macintosh, the only button), without moving your mouse. "Click" is usually understood to mean "single-click." If the mouse "cursor" on the screen is the "arrow," all that matters when you click is the location of the very tip of the arrow.

Clicking has a number of uses. For example:

In the text of a document or email you're writing, a single-click places (or moves) the "insertion point," that vertical blinking line that determines where the text you type will be inserted.
Clicking on a vertical scroll bar scrolls the content of your window up or down.
Clicking on a menu title or a pop-up menu reveals the items in that menu, e.g., clicking on the menu title "File" or clicking on a font menu.
Clicking on an item within a menu performs an action, e.g., clicking "Print" in the File menu.
Clicking on a "button" in a window or dialog also performs an action. Examples of common buttons are the "B" in a toolbar to make your text bold, and the buttons in the corner of your window that minimize, maximize, or close that window, as well as buttons in dialog boxes labeled "OK," "Cancel," "Yes," and "No."
Clicking on a document or folder icon typically selects that icon. This enables you to do things to the icon such as rename or delete it, create a shortcut to it (or an alias on Macintosh), or find out how much space it takes up. (Note that on Windows, there is an option that makes single-clicking on a document or folder icon open the item immediately instead of selecting it. This is another reason this topic so confusing.)
Clicking on an item in a scrolling list (e.g., a list of documents or a list of email messages) selects that item, enabling you to open it, delete it, or perhaps move it to another folder.
Clicking on a link on a web page takes you to another web page. Try to be patient, since the speed of your internet connection may vary.
When you find yourself presented with a set of mutually exclusive choices, each with its own little "clickable" circle, those are called radio buttons. (These were named after the big buttons on old car radios. When you pushed in one button to choose a preset station, the previously chosen button popped out.) Clicking on a radio button lets you choose one option from among many. For example, when you Print you may see the choices "All pages," "Current Page," and "Page range."
Clicking on a checkbox lets you turn a single option on or off, such as the "Collate" option when printing.

What's a double-click? What's it for?
A double-click consists of two clicks that are performed quickly, without moving your mouse, using the left button if you have a two-button mouse. If you click too slowly or move your mouse, your clicks may be treated as two separate single-clicks. You can adjust this "threshold" to some degree in the Mouse options in the Control Panel on Windows, and in System Preferences on Macintosh.

Double-clicking has a number of uses. For example:

It opens a folder icon so you can see its contents.
It opens a document icon so you can see (and perhaps edit) its contents.
It opens a program icon so you can start to use that program.
If you're in a scrolling list (for example, of email messages), it opens an item in the list.
If you're editing some text (in a document or email message), it selects the entire word under your cursor.

In general, if single-clicking an item does something, double-clicking it may do more. For example, you can use single-click to select vs. double-click to open.

Double-clicking when you "shouldn't"
Imagine double-clicking on an item that isn't designed for it. Here's what may happen:

It may have no effect at all, like clicking a second time on the same radio button.
You may simply undo what you did. For example, double-clicking on the bold "B" toolbar button makes your text bold and then plain again, and double-clicking a checkbox may turn it on and then off again.
You may cause two things to happen when you only wanted one. For example, if you're placing an order on a web site and you double-click the "Place my order" or "Submit" button, you may place two separate orders (causing two separate charges to your credit card). If you double-click the printer icon in a toolbar, you may print two copies of your document.
Your second click may cause unpredictable results. For example, if you double-click to close a window or on an OK button, the entire window you clicked in disappears and whatever was behind that window is revealed and may in turn react to your second click.

The key idea here is to recognize what type of item you're clicking on and what result you want, and learn to click appropriately.

Hidden gems of clicking / Can I triple-click?
When you're working with text (e.g., in Microsoft Word or certain email programs), there are many labor-saving variations of clicking:

Single-clicking: This places (or move) the "insertion point," that vertical blinking line that determines where the text you type will be inserted. And, if you keep holding down the mouse button and "drag," you'll also select some text.
Double-clicking: This selects the entire word under your cursor in one step. And, if you keep holding down the mouse button after double-clicking and "drag," you'll also extend your selection by entire words.
Holding down the Ctrl key on Windows (Command or Apple key on Macintosh) and clicking: This selects the entire sentence. And, if you keep holding down the mouse button and "drag," you'll also extend your selection by entire sentences.
Triple-clicking: This selects the entire paragraph (or the entire line, depending on the program). And, if you keep holding down the mouse button and "drag," you'll also extend your selection by entire paragraphs (or lines).

Where to go from here

If you're in the habit of double-clicking almost everything, try single-clicking. If you get the same result, you'll save some time and effort!
If you find that some items do what you want with a single-click but others require a double-click, try to notice the difference, especially their appearance or context. Still confused? Ask me!
If your mouse moves too quickly (or slowly), or you have trouble clicking fast enough to do a double-click consistently, you can adjust your Mouse settings by going to the Control Panel on Windows or System Preferences on Macintosh.

If you know someone who might find this helpful, please feel free to forward it.
If you have any comments about this article, send me a reply!
If you have a topic that you'd like me to write about, I'd love to hear about it!