The search bar on tree views( for table of contents, annotations etc ) on the left sidebar is not short lisiting the root items in the tree view on searching.

For example, in this file http://www.publishers.org.uk/_resources/assets/attachment/full/0/2091.pdf
if I search for Introduction, it doesn't show up.

Ideally, it should shortlist it.

Reproducible: Always

Steps to Reproduce:
1. open http://www.publishers.org.uk/_resources/assets/attachment/full/0/2091.pdf
2. search for Introduction in the table of contents.

Actual Results:  
Nothing shows up in table of content tree view.

Expected Results:  
It should shortlist introduction in the table of content tree view.