In case some Windows people want to experiment (and aren't following the Maverick Crashing thread). I've posted (Google Drive link) the Windows build of Sigil patched with KevinH's "Preserve Entities" feature (and with Qt5.3.1). The named entities you wish to be preserved (when editing in Book View) must be entered in the new
Edit > Preferences > Preserve Entities section of Sigil's settings.
I'm sure there's probably some sort of daily download limit for files on Google Drive, but I'm thinking we probably won't have to worry about it (but I thought I'd mention it just in case).
Anyway ... make of it what you will.
https://drive.google.com/file/d/0B5C...it?usp=sharing