Running JavaScript profiling on both desktop and mobile the majority of time is spent in jQuery.extend.css - the majority of which seems to be caused by ve.ce.ProtectedNode.prototype.onProtectedSetup
On mobile this seems to be even more severe.
In desktop 7.9% of execution time to load VisualEditor was spent in jQuery.extend.css - this was the most heavy function. In mobile it was also the most heavy - however in mobile a whopping 23.76% of time was spent in jQuery.extend.css
Stubbing out the contents of the foreach loop
this.$element.add( this.$element.find( '*' ) ).each( function () {
seems to remedy this problem.
Version: unspecified
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=51202