Undo a display expression, ... or display identifier, ... command.
Undo the display commands numbered n, ...
Undo all display commands.
where:
expression is a valid Java expression.
field_name is the name of a field in the class.
identifier is a local variable or parameter, including this, the current class instance variable (object_name.field_name) or a class (static) variable (class_name.field_name).