Dialog boxes are commonly used in applications to retrieve input from the user. In some applications a dialog box is used to prompt the user for input and once the application retrieves the input the dialog box is automatically closed or destroyed.

On the other hand, some applications use dialog boxes to display information while the user works in other windows. For example, when you check spelling in Microsoft Word a dialog box remains open so you can go through and edit your text in the document while the spell checker looks for the next misspelled word. To support the different ways applications use dialog boxes, C1Dialog supports two different types of dialog windows: modal and modeless dialog windows.