Access: Read Write
Whether or not the label contains an underline for a mnemonic. If this property is true any underlines in the label will be treated as mnemonic identifiers. If the property is false any underlines will be shown literally in the label.
If a label contains two underlines and user_underline is true, both underlines will be shown as mnemonics, but only the second underline will work.
Defaults to false.
See also: set_use_underline()