Home > Articles > Programming

Bad UI of the Week: Ask Forgiveness, Not Permission

Undo commands have been around for a long time, but programmers still use them only intermittently. David Chisnall looks at some of the things that are often missed.
Like this article? We recommend

Like this article? We recommend

Safari 3 came out not too long ago and half-fixed my pet peeve with the UI—that it was far too easy to close tabs by mistake. I generally close a tab by hitting Command-W. On a QWERTY keyboard, W is next to Q, and accidentally hitting Command-Q would quit the application, closing all tabs (and windows).

To me, this seemed like an obvious violation of Raskin’s First Law: A computer shall not harm your work or, through inaction, allow your work to come to harm.

In most cases, the contents of the pages weren’t destroyed, but I regard all parts of user-visible state as important. I rely heavily on spatial memory while working. Even if I open the same tabs again, I’ve lost their positions onscreen, so it takes longer for me to switch to them again.

In other cases, it’s much worse. If I’d been using a web app or filling in a web form when I accidentally closed the program, I could have lost a lot of state information. While it probably doesn’t count as work, I’ve lost a few long Slashdot posts as a result of that slip of the finger.

Some older browsers I’ve used make this last action even easier. If you accidentally click a link while filling in a form, when you hit Back the form contents will have gone. This is something that Safari does right: Form contents are cached with a page, so the Back button restores the previous page.

The first browser I used that correctly handled accidental quitting was Opera. In Opera, if you quit the application and then re-launch it, all of your tabs will be exactly where you left them. Firefox does something similar if the browser crashes, which protects users somewhat from developers’ errors, but not from their own.

This isn’t what the new version of Safari and current versions of Firefox do, however. These versions ask you to confirm that you want to close the browser. Now, it might be argued that closing a browser is something that happens infrequently enough in a modern computing environment that it should be confirmed. The problem comes when closing is something that happens more frequently.

To prevent you from losing form data through closing a tab, Safari now asks you to confirm that you want to close any tab containing form data. Very quickly, you get into the habit of closing tabs with Command-W immediately followed by Enter. For the first couple of times you accidentally close a tab, this habit might help you. Beyond that, you’re so used to automatically hitting Enter to dismiss the warning dialog that you don’t even do it consciously.

What would be a better way of getting the user to confirm the loss of form data? For some inspiration, let’s look at how browsers get around the problem of losing form data when you click a link. To recover the data, all you do is hit the Back button. Of course, the Back button in a web browser is just a specialized form of an undo feature; it undoes a single kind of action, namely navigation.

Since most browsers have some kind of undo feature already, why not generalize this capability to allow reopening tabs or windows that have been closed? Don’t ask me to confirm that I want to close a window—just close it. If I made a mistake, let me use undo to bring it back. Safari 3 almost gets this right; you can un-close a window (but not a tab), and you can restore all windows and tabs from the last session, but these options are hidden in the Bookmarks menu, far away from where undo options usually live.

Sometimes implementing undo isn’t even possible. Once an email message has left the user’s machine, for example, it’s beyond the mail client’s control. Nothing the client does can change this situation (much to the distress of a great many email users in the early hours of the morning, after some heavy drinking). Anything that sends data to a remote system that’s not under the user’s control can make an undo feature impossible. In some circumstances, it might be worth asking for confirmation first. Sending email isn’t one of those instances, though, because the user will get used to confirming automatically. All the dialog box will do is waste time.

In most other cases, a confirmation dialog could easily be replaced by an undo feature. If the user actually meant what he told the computer to do (which sometimes happens—users aren’t always wrong), avoiding the confirmation process means less time spent being distracted by pointless controls. If the instruction was accidental, an undo feature gives the user longer to catch the error.

Unfortunately for users, most development environments make it much more difficult to implement a global undo feature than to create a proceed/abort dialog box. In most cases, the dialog box takes only a single line of code, whereas setting up a global undo can require a lot of data structures and other housekeeping tasks. Of course, a good application will keep an undo buffer anyway, but making sure that everything is added to it can be non-trivial.

As the saying goes, it’s better to ask forgiveness than permission. This is completely true in the context of user interface design. If it’s possible to allow the user to undo an action, then it’s always preferable to do that, rather than asking for confirmation first.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020