Function cutoff_for 

pub fn cutoff_for<'a, R>(
    columns: &[Column<'a>],
    rows: &[R],
    sizing: &Sizing<'_>,
    style: &TableStyle,
    width: u16,
) -> Priority
where
    R: AsRef<[Cell<'a>]>,

The weakest cutoff whose columns fit in width.

Raised until the layout fits, and never past Priority::Essential: the essential columns are what makes a row identify itself, so a window too narrow for them gets them truncated rather than dropped. Nothing here counts positions, so which column drops is a property of the column.