User blog comment:Kirkburn/Syntax highlighting - helping you read and write code/@comment-126761-20150325201010/@comment-126761-20150330160131

Regarding lag on long pages - that shouldn't still be happening, but it's possible our optimizations didn't go far enough. Please do send in a Special:Contact report about this, so we can look into this in more detail.

I'll pass on the highlighting improvement ideas - thanks!