Why do we need to set exactly height for listview to let ListView render footer ?

if i set listview height caculate automatically base on flexbox layout, so if some item view existed overfloat screen, we can't render footer.
I must set height: 300 to let listview can render footer.
It take me 1 afternoon day.

Start by reproducing the issue with a flexbox-sized ListView whose items extend beyond the screen, then inspect the ListView layout and footer rendering path. Done means the footer renders without requiring a fixed height such as 300.

Written by the indexing model from the issue text.