Before this commit, when the list view is rendered and is empty then the state and priority columns are relatively big just to display a button. This commit fixes the width of those columns to 40px when the list view is empty. If the list view is not empty then those columns will have a min-width set to 40px. task-3248592 closes odoo/odoo#120508 Signed-off-by: Xavier Bol (xbo) <xbo@odoo.com>