Creates a new MenuItem.
If label
is non-null it is used to set the "label" attribute of the new item.
If detailed_action
is non-null it is used to set the "action" and possibly the
"target" attribute of the new item. See set_detailed_action for more
information.
label |
the section label, or null |
detailed_action |
the detailed action string, or null |
a new MenuItem |