Okay, this is tricky. I am not sure we can know if it is meant to be flex or block here. This was added to support bootstrap 4 style animations in inferno-bootstrap. https://github.com/jhsware/inferno-bootstrap/blob/be4a17bff5e785b993a66a2927846cd463fecae3/src/Modal/AnimateModal.js  I would like to keep it but add a comment about why it exists so it potentially can be removed in the future.