EClass provides the functionality to undo a previously executed "updating command." The defined "updating commands" are as follows:

• Modifying the contents of the editor (while preparing a lecture).
• Creating, modifying, or deleting Snapshots, Overlays, or Sticky Notes.
• Creating, modifying, or deleting Shapes.
• Changing permissions for any student(s).
• Editing the contents of any text entry area (including the chat window).

The 25 most recent "updating commands" are stored at any given time. When the user chooses the 'Edit -> Undo' menu item, the most recent "updating" command is undone. The precise definition is that EClass is returned to the state it was in immediately prior to the issued command. If no "updating commands" have occured since EClass was opened, or a save was preformed, then Undo has no effect.

Undo only applies to the "updating commands" and itself, not to any other commands. Specifically, Undo does not apply to:

• Find,
• File commands,
• Edit commands except itself,
• Cancel or Clear commands in any interface dialog.

Operating systems typically provide a "clipboard" area through which cut and paste editing commands operate. EClass utilizes the operating system's clipboard for Cut, Copy, and Paste operations.

To use the Cut or Copy commands, the user first selects a section of text within a text box. The Cut command first copies the selected text to the clipboard, and then removes the selected text from the text box. The Copy command copies the selected text to the clipboard; the contents of the text box remain unmodified. If the user has not selected any text, the Cut and Copy commands have no effect.

The Cut command is only applicable to editable text boxes. Selecting the Cut command on a selection within a read-only text box will have no effect. The Copy command is applicable to both editable and read- only text boxes.

To use the Paste command, an editable text box must be selected. When the user selects the Paste command, the last selection copied through the Cut or Copy commands is inserted at the cursor position in the text box. If no text has been copied, the Paste command has no effect.

The Cut, Copy, and Paste commands only affect plain- text within text boxes. At this time, Shapes, Overlays, Snapshots, or other aspects of the EClass application cannot be cut, copied, or pasted.