query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets

query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|/sitecore/content
// yields only 1st root, the query, content-root isn't there.
datasource=query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|/sitecore/content
// yields 2nd root correctly, 1st root defaults to /sitecore root
datasource=query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|datasource=/sitecore/content
// both roots are now defaulting to /sitecore root
datasource=query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|datasource=query:/sitecore/content
// again both roots now /sitecore root
query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|query:/sitecore/content
// yields nothing, no roots shown, completely empty field in content-editor