We do not take CSS seriously enough, but it has an impact on rendering
speed. The rule removed in this commit slowed down the Qunit JS test
suite by a considerable amount:
With a fresh db with no extra addon installed, community version:
- in chrome, before this commit: 103.2s, with this commit: 54.8s
- in firefox, before this commit: 194.9s, with this commit: 117.7s
This is due to the way rendering is done in web browser. They start
checking css rules from the right, so the *:nth-last-child(2) rule was
checked for every element in the dom, each time it was added/modified.
Note that the rule just above (*:first-child) had no noticeable impact,
but I still think that the universal css selector should still be
avoided in general.
The fun part is that I did not find the place where this rule was
supposed to be applied. I assume that it is just a dead rule. If this
is not the case, we can reintroduce the margin-top with the class mt0,
applied on the specific element.
Géry Debongnie
75b0393454