The per-view action+toolbar row is a HorizontalLayout whose sized children
are conditional per tab. When they are absent its auto vertical-stretch
becomes 1, so it split the leftover height with the scrolling content. The
Flickable-based tabs (artists/playlists/labels) have a small content
preferred height, leaving slack the row grabbed -> a giant empty sub-header.
Tracks/Albums looked fine only because their content fills. Pin the row to
vertical-stretch: 0 so the content always absorbs the slack.
cc
vicrodh
da683cd5d0