March 1998

The Tab Control

A tab control in Windows software organizes a great deal of information in a single window. The tab control looks like a set of dividers in a file cabinet. Each tab has a label, and when you click on the tab, you see the settings described by the label.

Figure 1 shows setup information for RTG Bills, our legal time and billing software, organized as a tab control. Notice that the "Firm" tab has been selected. The panel displays the Firm Name and Address and a checkbox for a setting which affects all of the firm's bills.

Figure 1. A tab control
Figure 1. A tab control

Tab Navigation

As you would expect, you can click on a tab to bring it to the front. Less obvious is that there are keystrokes you can use to move from one tab to the next.

Here is how you can select a tab with the keyboard. First press the Tab key one or more times until the "input focus" is on the label of the selected tab. You will know the label has the focus when you see a box around the label. Now use the left and right arrow keys to move from one tab to the next. The combination Ctrl-Tab is equivalent to the right arrow key.

Once you have selected a tab, press the Tab key again to move to the item you want to change on that panel.

Tab Confusion

Sometimes the tab control can be confusing. A window with a tab control generally has three buttons along the bottom: OK, Cancel, and Apply. The buttons are intended to refer to the entire window, which is consistent with their placement outside the individual panels.

In other words, if you click Cancel, you are rejecting the changes you have made on all the panels, not just the current one. Similarly, if you click OK, you are accepting all the changes on all the panels.

The Apply button is like OK, except it doesn't close the window. This is useful if the changes affect the screen display, so you can see the changes and judge whether or not you like the current settings. In the figure, the changes do not affect the screen so we do not have an Apply button.

While we were researching the use of tab controls, with the intention of including them in future releases of RTG Bills, we came across an interesting article by User Interface Engineering, a consulting company. The article states that users often expect the Cancel button to refer to the current tab, not the entire window. A user will make changes to one or more tabs, select a tab which requires no changes, and click Cancel. The user meant to say "no changes required on this panel," but the tab control ignores all the changes on all the panels.

More Tab Confusion

Another confusing feature of tab controls arises when the control contains more than one row of tabs. The front row works as you would expect. If you click a tab in a back row, however, that entire row jumps to the front. Suddenly all the labels seem to be in different locations, which we find very disorienting.

In fact, it wasn't until recently that we understood what was happening: the rows move, but the tabs within each row maintain their positions. It always seemed as though the tabs were being completely rearranged.

Microsoft's user interface guidelines for 32-bit Windows software include this suggestion:

By default, a tab control displays only one row of tabs. While the control supports multiple rows or scrolling a single row of tabs, avoid these alternatives because they add complexity to the interface by making it harder to read and access a particular tab.

Tab Controls In RTG Bills

In spite of these problems, we feel that tab controls can be useful for reducing the amount of information presented at one time. The window shown in Figure 1 replaces two menu items, Setup, Data Entry and Setup, Other. Instead of having two large windows with many items in each, we now have six smaller panels with a few items on each one. Each panel also has its own help screen, and we have added the Help button to display it.

We hope to reduce the confusion associated with the Cancel button by asking the user to answer this question: "Discard changes to ALL tabs?" Clicking Yes discards all changes. Clicking No returns the user to the tab control without affecting the changes.

We considered another alternative: replace both the OK and Cancel buttons with a single Close button. The result would be that changes would always be saved when you closed the window. You would never accidentally discard changes which you wanted to keep.

Of course, the disadvantage of removing the Cancel button is that you can't cancel your changes! Not only that, but the tab control in RTG Bills would be different from all other Windows programs. We decided to keep the standard OK and Cancel buttons and accept the inconvenience of having to confirm your intentions after you click Cancel.

The second problem, the confusing behavior of multiple rows of tabs, is easily avoided by only having a single row of tabs.

The tab control will make its first appearance in the next version of RTG Bills.

Free Netscape Navigator

Netscape's Web browser started life as a free product which anyone could download from For a while you had to buy it. Now it's free again.

Microsoft's Internet Explorer, which is Navigator's only significant competitor, has always been free. With Netscape's market share slipping, it came as no surprise when Netscape announced this change.

Communicator Standard Edition combines Navigator with e-mail, discussion groups, a Web-page editor, and conferencing. It is also free. To add a calendar with group scheduling, get the Professional Edition for $29.

RTG Bills and RTG Timer are trademarks of RTG Data Systems. Other company and product names may be trademarks of the companies with which they are associated.

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