OK, I’ll start again:
AS A USER, I WANT THE NAVIGATION PANEL TO HAVE INSTANT INTERACTIVITY. I do not want to wait for a spinner on every single click of “expand.” I do not want to have to wait for the same spinners every time I navigate to a new page. As for your questions:
It takes 200ms - 1000ms per expand click. Anything less than instantaneous is unacceptable.
Top level: 5 categories. Next level: 7 - 19 categories (which seems immaterial, since you cap the responses at around 15 and slap a “more” label that has to be clicked leading to a spinner.)
Ubuntu 16.04
xwiki-enterprise-common/stable,now 9.4
xwiki-enterprise-mysql-common/stable,now 9.4
xwiki-enterprise-tomcat8-common/stable,now 9.4
xwiki-enterprise-tomcat8-mysql/stable,now 9.4
libmysql-java/xenial,now 5.1.38-1
mysql-client-5.7/xenial-updates,xenial-security,now 5.7.19-0ubuntu0.16.04.1
mysql-client-core-5.7/xenial-updates,xenial-security,now 5.7.19-0ubuntu0.16.04.1
mysql-common/xenial-updates,xenial-security,now 5.7.19-0ubuntu0.16.04.1
mysql-server/xenial-updates,xenial-security,now 5.7.19-0ubuntu0.16.04.1
mysql-server-5.7/xenial-updates,xenial-security,now 5.7.19-0ubuntu0.16.04.1
mysql-server-core-5.7/xenial-updates,xenial-security,now 5.7.19-0ubuntu0.16.04.1
Running on an AWS t2.small instance.