Ctrl-A Bug in Mozilla Internet Suite



Mozilla Internet Suite makes use of many of the standard shortcut commands that most Internet browsers use. A shortcut command is a combination of keys that, when pressed in unison, causes an action within the program. For example, pressing Ctrl-A on this Internet page will select everything that is on this page. However, the browser has an error that causes it to incorrectly highlight text within forms. Instead of highlighting the text, the Ctrl-A command simply moves the cursor to the front of the text.

Application Description

Mozilla Internet Suite is a free web suite designed by Mozilla.org. Included in the suite are an Internet browser, an address book, a mail and newsgroup reader, and a program debugger.

Test Design

This example demonstrates the use of Function testing. In Function testing, we evaluate the application by locating and isolating functions, then interacting with the functions and observing how well each can perform its task.

For this presentation, we will be specifically evaluating the "select all" shortcut command (Ctrl-A) function. This is a commonly used feature of many graphic user interface applications, and therefore it is an important component. We will navigate through the browser, utilizing Ctrl-A in different circumstances to ensure that it performs the expected task correctly. One such common circumstance is forms, which are parts of web pages that allow a user to input text. We will also use the Ctrl-A shortcut command to select allof the visible components in an area or page to allow the user to copy/paste them. For example, pressing Ctrl-A on this page would highlight all of the text, the pictures, and the page separators.

Function testing is a powerful testing technique in that we can see exactly what one function outputs from a specific input. We are giving an input of some text, and we are expecting the function to highlight (rather, to select) that text. We can directly observe if the function does this correctly.

Performing the Test

  1. Open the Mozilla browser:

  2. Navigate to a page with a text field form. For instance, on the Yahoo! Search Engine site, there is a text field where we would input a search string for Yahoo! to look for on the Internet. Once there, enter some text into the text field, like below:

  3. Now, with your cursor inside the text field, press Ctrl-A on the keyboard to select all of the text you just typed in:

    Before pressing Ctrl-A

    After pressing Ctrl-A

  4. To verify what this function should do, click in the white space of the background on the Yahoo! site and press Ctrl-A


When we clicked in the general background and then pressed Ctrl-A, all of the text and pictures on the page were selected. However, when we pressed Ctrl-A inside of the text box, nothing was selected and the cursor was moved to the beginning of the text field.

This bug is important because many users use the Select All feature to cut and paste information from one form field into another. For example, if all of the same information from one field is also required in another, the user can simply copy the text in the first field and paste it into the other. The problem is that the shortcut command for selecting all of the text in order to copy it does not work properly.

The actual cause of the bug is that Linux has typically utilized the command Alt-A for selecting all of the text inside of a text box. However, the browser recognizes (and lists in its specifications) that Ctrl-A is the proper command. Ctrl-A will highlight all of the data outside of a text box, and Alt-A will highlight all of the data inside of a text box. That means that a user must use two different commands (one of which is not listed) to perform the same task.

This bug is not critical and does not affect the program in any serious way, but it certainly presents an obstacle to ease of use.

Function testing allowed us to quickly and easily find this bug because we simply targeted one function with as few other variables as possible. By working with only one text box and all other options as default, we could see exactly how this function performed with the text that we had.

Similar Tests/Additional Notes

Try using some of the other Internet browsers, such as Opera or Internet Explorer, and attempt to use Ctrl-A inside of text fields. Do they work the same way?

Configuration Notes

Testing Mozilla's Internet Suite v1.4.1 on:

Created 26 May 2004 for the CSTER

All images and written material ©Copyright Sam Oswald 2004

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