UNDO
ONCE ONLY IF YOU'RE LUCKY
IMPLEMENTING MULTIPLE UNDOS IS (A LOT) MORE COMPLICATED
procedure TEditorForm.EditMenuUndoClick(Sender: TObject);
begin
{SORT ME: currently will not cause the deletion of text that
has been inserted from the clipboard, for instance...}
{AND WILL ONLY UNDO (SOME OF) THE LAST EDIT OPERATIONS...}
SendMessage(Editor.Handle, EM_UNDO, 0, 0);
end;