fn ensure_after_not_empty(&mut self) {
        if self.after.is_empty() && !self.before.is_empty() {
            self.after.push_front(self.before.pop_back().unwrap());
        }
    }
// If there is no element focused, try to focus the last element.
If there is no element focused, try to focus the last element.
If there is no element focused try to focus the last element .
fn ensure_after_not_empty(&mut self) {
        if self.after.is_empty() && !self.before.is_empty() {
            self.after.push_front(self.before.pop_back().unwrap());
        }
    }
fn ensure_after_not_empty ( & mut self ) { if self . after . is_empty ( ) && ! self . before . is_empty ( ) { self . after . push_front ( self . before . pop_back ( ) . unwrap ( ) ) ; } }
If there is no element focused, try to focus the last element.
If there is no element focused try to focus the last element .
&mut self