Reverses (one at a time) a series of editing actions
Redo
Reverses (one at a time) a series of Undo actions
Cut
Deletes the currrent (merge text) selection and places it on the clipboard
Copy
Copies the current selection to the clipboard
Text can be selected by pressing and holding down the mouse
button within a difference or merge view window. Then, moving the mouse
to highlight the desired text.
Paste
Pastes the contents of the clipboard at the insert point (in merge text)