Wherever there are lists and edit boxes, the tab key allows you to cycle which one is in focus, mouse clicks choose focus and select items, and the arrow keys can be used to move within or between items.
In addition, many of the lists have double-click shortcuts. In the Edit Link lists, double-clicking the mouse brings up the Modify Dialog; in the Document Title list it brings up the Assign Dialog; and in the Contents list it is equivalent to using the View button. Double-clicking items in the Assign dialog has the effect of moving the items between the two lists there, and double-clicking the Contents list with the Option key held down brings up the Location dialog.
The Contents pane of HTML Author has standard Command-key shortcuts associated with it; namely, Command-N for the New button, Command-A for Select All, and Command-S for Export HTML (Save). The Cut, Copy and Paste menu items are available for all edit boxes, and correspond to the keyboard shortcuts Command-X, Command-C and Command-V, respectively.
The OK and Cancel buttons on the bottom right of the main dialog apply to everything done since last invoking the HTML Author Plug-in. The only exception to this is that Cancel does not remove files previously saved to disk with the Export HTML button. However, it does cancel the document records created since the last invocation.
