pub fn focus_previous(&mut self) {
        if self.before.is_empty() {
            swap(&mut self.after, &mut self.before);
        }
        if let Some(elem) = self.before.pop_back() {
            self.after.push_front(elem);
        }
    }
/// Shifts focus to the previous element.
Shifts focus to the previous element.
Shifts focus to the previous element .
pub fn focus_previous(&mut self) {
        if self.before.is_empty() {
            swap(&mut self.after, &mut self.before);
        }
        if let Some(elem) = self.before.pop_back() {
            self.after.push_front(elem);
        }
    }
pub fn focus_previous ( & mut self ) { if self . before . is_empty ( ) { swap ( & mut self . after , & mut self . before ) ; } if let Some ( elem ) = self . before . pop_back ( ) { self . after . push_front ( elem ) ; } }
Shifts focus to the previous element.
Shifts focus to the previous element .
&mut self