Neither of us seem to be a fan of the expand/collapse feature in Oracle, nor the navigation bar. However it was Connor that took the time to find a simple edit to restore the look and feel to pre 11g levels.
Where your local version of the documentation is stored, simply rename this file
And instead of the documentation looking like this on entry, requiring more clicks to do anything of use:
It will look like this, all ready to search for your keyword of interest:
The main page will retain it's little search area, although if you use that, it will search online - so you might as well utilise something a little more powerful and handy like Ubiquity.
I don't know what the folks at Oracle Documentation HQ think of this, but at least it's not tinkering unlawfully with the database.