searchtools: Don't use slideDown to show search results. #8868
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Fixes a performance issue with massive lists like sphinx-doc#8562. jQuery.slideDown is pretty bad perf-wise since it thrashes layout multiple times. The 5ms animation is unnoticeable (it last less than an animation frame!) and just burns CPU cycles unnecessarily in all browsers. On Firefox this is specially bad because it hits a performance cliff with list items / CSS counters (https://bugzilla.mozilla.org/show_bug.cgi?id=1683910#c26 for all the gory details) where it causes tons of counter recalc. An alternative fix for the Firefox cliff would be to set overflow: hidden on the list item, but I think removing the animation is probably more sensible, given that as I said it's just burning CPU. Fixes sphinx-doc#8562
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Subject: Don't use slideDown to show search results.
Feature or Bugfix
Purpose
Detail
Fixes a performance issue with massive lists like #8562.
jQuery.slideDown is pretty bad perf-wise since it thrashes layout
multiple times on all browsers. This is specially bad on slow machines.
The 5ms animation is unnoticeable (it last less than an animation
frame!) and just burns CPU cycles unnecessarily in all browsers.
On Firefox this is specially bad because it hits a performance cliff
with list items / CSS counters
(https://bugzilla.mozilla.org/show_bug.cgi?id=1683910#c26 for all the
gory details) where it causes tons of counter recalc.
An alternative fix for the Firefox cliff would be to set overflow:
hidden on the list item, but I think removing the animation is probably
more sensible, given that as I said it's just burning CPU.
Fixes #8562
Relates