Vertical toolbar still flickering

Problem/Motivation

When toolbar is in vertical mode, it's still flickering.

Steps to reproduce

It can be easily reproduced by disabling javascript on the browser. It shows the "broken" interface before javascript runs.

Proposed resolution

I found that javascript manages to insert certain classes that are vital to the vertical layout. These critical classes can be populated by php instead since toolbar_anti_flicker has already introduced cookies to store toolbar states.