Windows can display a title in a title bar or in the combined title bar/toolbar area. When a title is displayed, it’s typically the name of the app, the name of a document, or the name of a specific type of functionality, such as Inspector.
For some windows, a title isn’t necessary because there are other elements that help users identify the window. For example, Game Center (shown here), App Store and iBooks all display recognizable toolbar icons that make a title unnecessary.
If you want to use a hidden title bar, be sure that users can still get the information they need from other areas in your window. Also, users need to be able to move a window by dragging a window-frame area, so you want to make sure that the toolbar doesn’t become too crowded. For example, Safari hides the title bar, but it displays webpage titles in the URL bar and lets users move the window by dragging from the area around the URL bar.
If you decide to display a title in your window, follow these guidelines.
Use your app name for the title of a main, nondocument window. If your app has a short name, use it as the title. For more information about the short name, see The App Menu.
Name a new document window “untitled.” Leave “untitled” lowercase to make it more obvious that the window contains untitled content. Don’t put a “1” on the first untitled window, even after the user opens other new windows.
If the user chooses New again before titling the first untitled document window, name the second window “untitled 2,” and so on.
If the user dismisses all untitled windows, the next new document window they open should start over as “untitled,” the next should be “untitled 2,” and so on.