Cannot preview a PDF contained in a Zip file

A PDF in a ZIP file is previewed as ASCII file

Take a 10.10-HF-ed release

• Create a ZIP file containing a PDF with a name such as "Support.pdf"
• Create a File document with the ZIP as file:content
• Preview the ZIP file: it lists the files inhe ZIP as links
• Click on the link "Support.pdf" : it displays as text file!

Expected result in 10.10: PDF in the ZIP file displayed as PDF file

In nightly.nuxeo.com, the ZIP preview is currently failing in attempting to display the ZIP as a PDF, which is also wrong

Expected result on nightly: ZIP preview listing the content of the ZIP and then PDF displayed as PDF