A second run replaced the first on screen with no way back. Results now
accumulate in the Assets panel across runs, and the bin owns what the
viewer shows: the session subscription drove the viewer as well, so every
progress message walked a click on an older result back to the newest.
Grid, list and icons are one collection in three shapes, sharing selection
so switching view is not a way to lose it. No <video> thumbnails, ever --
that is v4's connection-pool stall. A thumbnail that does not arrive falls
back to the glyph rather than the browser's broken-image icon.