There are now 3 code paths in decreasing speed:
First, optimize subsearching more by just hiding the actors
that didn't match, since we know the ordering has to be right.
For initiating a search (or backspacing an existing one), again
instead of destroying and recreating actors, just temporarily
remove them and re-add them in the desired order.
Finally for when data has changed, use the old code path of
destroying all actors. (This itself could obviously be optimized
if we had a way to know that just one application changed, but
at the moment we don't).
https://bugzilla.gnome.org/show_bug.cgi?id=596119
159081dcfc