It there a way to enable content indexing (through windows search) for version 3.5 on Windows 7x64 or is it is unfixed bug (hopefully not unknown). It finally started working in version 3.4.5, and I was extremely disappointed to see go away again in 3.5.
Hi @erbil_e_ciffo, Are you still experiencing this bug using the latest builds of LibreOffice? Please let us know! 
This was supposedly fixed in 3.4.4:
https://bugs.freedesktop.org/show_bug.cgi?id=36950
I would suggest opening a new bug report, while referring to the older bug.