First, a thanks for the greatly improved documentation site at book.cakephp.org; especially since you converted the old documentation as well.
However, there is one thing that is annoying me immensely 
. Whenever I scroll up or down through the documentation (and this happens a lot), the red top menu pops in and out of view, which is:
a) highly distracting
b) often covers the sentence I just wanted to read, so I need to scroll some more.
I would suggest to make that menu static, expand-upon-click or expand-upon-hover (my order of preference).