The previous deleteLater on the QPropertyAnimation left a dangling
self._fade_anim reference to a dead C++ object. When the next
search called FlowLayout.clear(), calling .stop() on the dead
animation threw RuntimeError and aborted widget cleanup, leaving
stale thumbnails in the grid.
Now the finished callback nulls self._fade_anim before scheduling
deletion, so clear() never touches a dead object.
pax
60cf4e0beb