Children of prefix-grid should not have height: 100% on legacy. This rule is necessary for the modern CSS Grid implementation or the children will have no height.
When a legacy item is brought back from display: none, we should not assume that it uses display: flex. Instead, we should set the default to display: block.
prefix-gridshould not haveheight: 100%on legacy. This rule is necessary for the modern CSS Grid implementation or the children will have no height.display: none, we should not assume that it usesdisplay: flex. Instead, we should set the default todisplay: block.