>Ideally we would load it in overlay.xul and this check would not be necessary.

Should I just move it to `overlay.xul` then? Or is there something keeping it in `zoteroPane.xul`? (I don't see anything obvious, but it's also quite late)

The only call I see to `Zotero_Browser` that might not be Firefox-specific is [here](https://github.com/zotero/zotero/blob/4.0/chrome/content/zotero/xpcom/mimeTypeHandler.js#L156), but that should probably fail for Zotero Standalone anyway, no?