Reduce Excise

Dialog boxes can be a burden on the user if they require a lot of excise—unnecessary overhead, which we discussed in Chapter 10. Users quickly tire of repositioning and reconfiguring a dialog box every time it appears. The duty of the dialog box designer is to assure that the excise is kept to a bare minimum, particularly because dialog boxes are only supporting actors in the interactive drama.

Know where you are needed

The usual ways dialog boxes fail to reduce excise are in their geographical placement and their state. Dialogs should always remember where they were placed the last time they were opened, and they should return to that place automatically. Most dialogs also start out fresh each time they are invoked, remembering nothing from their last instantiation. This is an artifact of the way dialogs are implemented: as subroutines with dynamic storage. We should not let these implementation details affect the way our programs behave. Dialogs should always remember what state they were in last time they were invoked and return to that same state. If the dialog was expanded or a certain tab was selected, the dialog should return the exact same way on subsequent visits. In Chapter 15, we discuss in more detail about how to apply memory to this type of problem.

The same idea can be applied to the contents of input fields. If a check box was checked last time, the dialog box should remember and come up with the box checked next time. Chances are good that the settings used the last time will be used the next time, too.

Know if you are needed

The most effective way that a dialog box (bulletin and process dialogs in particular) can reduce excise is to simply not appear if it is not needed. If there is some way for the dialog box to be smart enough to know whether it is really necessary, the program should—by all means—determine this and prevent the user from having to dismiss the unneeded box: an action that is pure excise.

For example, in Word, if you Save, Print, and Close a document in that order (something the authors do all the time), the repagination involved in printing marks the document as changed. This means that the program asks if you want to save it when you issue the Close command, even though you just did! The program should pay attention! Of course you want to save the document before closing. Not only should it not ask this question at all, it should be able to see that you didn't change it, the program did. The entire invocation of this dialog box is excise.

The same thing is true of bulletin dialogs that tell me that the program has completed some function normally. If it was so normal, the program shouldn't need to resort to the excise of a dialog box that stops the proceedings with idiocy.

If a program uses a dialog box to offer a selection of options every time you ask for a certain function, and you always use the same options, the program shouldn't bother to put up the dialog box. It should be able to recognize the pattern and remove the unnecessary step. Of course, it would have to inform you first (modelessly, please), so you're not surprised, and it should give you the option to override its decision.