Dialog Box - Document Modal

The concept of a document modal dialog has recently been used, most notably in Mac OS X and Opera Browser. In the first case, they are shown as sheets attached to a parent window. These dialogs block only that window until the user dismisses the dialog, permitting work in other windows to continue, even within the same application.

In OS X, dialogs appear to emanate from a slot in their parent window, and are shown with a reinforcing animation. This helps to let the user understand that the dialog is attached to the parent window, not just shown in front of it. No work can be done in the underlying document itself while the dialog is displayed, but the parent window can still be moved, re-sized, and minimized, and other windows can be brought in front so the user can work with them:

The same type of dialog box can be compared with the "standard" modal dialog boxes used in Windows and other operating systems.

Similarities include:

• the parent window is frozen when the dialog box opens, and one cannot continue to work with the underlying document in that window
• no work can be done with the underlying document in that window.

The differences are that

• the dialog box may open anywhere in the parent window
• depending on where the parent window is located, the dialog box may open virtually anywhere on screen
• the dialog box may be moved (in almost all cases), in some cases may be resizable, but usually cannot be minimized, and
• no changes to the parent window are possible (cannot be resized, moved or minimized) while the dialog box is open.

Both mechanisms have shortcomings:

• The Windows dialog box locks the parent window which can hide other windows the user may need to refer to while interacting with the dialog, though this may be mitigated since other windows are available through the task bar.
• The OS X dialog box blocks the parent window, preventing the user from referring to it while interacting with the dialog. This may require the user to close the dialog to access the necessary information, then re-open the dialog box to continue.