A dialog sheet is a dialog box or a modal screen attached to one window -- and one window only. It exists as of Mac OS X and is available on reprogrammed Carbon, as well as native Cocoa application programs.
A dialog sheet is movable, resizeable, and can even be minimized to the Dock. In some cases, it will be collapsible.
As of Mac OS X 10.3, two effects can happen when a dialog sheet appears:
- It can slide down. That is, true to the original word, it can appear from the top of the window and slide down to the bottom, much like blinds on a window or a vertical garage-door (not the drawbridge type).
- It can roll out. This can also be seen as a mailbox effect; the mouth of the postbox rolls open, and a letter is thrown into it. In this case, the sheet appears to roll toward you (in a Z-axis) before it actually rolls out completely; this is more 3D. This is new in Mac OS X 10.3. Dialog sheets that appear by rolling out often have a tiny horizontal line at the top of the sheet (think of it as the mouth of the letterbox).
Many navigational and control elements, such as buttons, check boxes, radio buttons, drop-down menus, input fields, scroll bars, panes, and other such items, can appear inside a dialogue sheet, ultimately making them very versatile.
Examples of Dialog Sheets
- Open and Save dialog sheets
- Confirmation alerts (e.g. "Are you sure you want to remove this picture?")
- Progress indicators (e.g. when Software Update launches, a dialog sheet rolls down with a progress bar, indicating that the Mac is checking for updates)