Function apply_change 

pub fn apply_change(
    path: &Path,
    key: &str,
    shown: Option<&SettingValue>,
    value: &SettingValue,
) -> Result<(), String>

A row changed from the window: only the cells the window changed, from what its row showed (shown, its words then) to value, set over the row as the configuration holds it now; a cell another device changed meanwhile stays. Without shown, every word of value.