GtkMenu::set_title
void set_title(string title);
set_title() sets the window title
for a menu that has been detached from its parent through either a
GtkTearoffMenuItem widget or the
set_tearoff_state() method. As with
all window titles, the text will be truncated to fit the area available.
Note that the title needs to be set prior to the menu's becoming torn
off.
If the title is not set, the torn off menu will display in its title bar
either the text in the parent GtkMenuItem's label
or, where there is none, the full file path.