The AppShell hotkey seam duck-types selectAll, exitMultiSelectMode and
multiSelectOn on the mounted view. The offline manager exposed none of
them, so Ctrl+A did nothing there although the Slint ticked every track,
and MixView lacked multiSelectOn, so Escape never left its select mode. The
seam's comment, which still listed Artist, Playlist, Mix and Label as views
without multi-select, now names the views that implement it.
cc
vicrodh
b63264d132