inactiveButtonsFlexFactor property
Flex factor.
Only set this combined with activeButtonFlexFactor!
By default, it is 160 : 60.
(this is a great package, so the flex is naturally pretty high)
Play around with these values, so that the text of all buttons and all icons are visible and there is no overflow - ideally on all screen sizes.
Implementation
final int inactiveButtonsFlexFactor;