On the last point, Emilio has informed me that root content documents are deliberately opaque by default. However, we support a `transparent="true"` field on `<xul:browser>`s, so perhaps geckoview could add an API which allows an embedded to opt in to using that.
Bug 1549943 Comment 6 Edit History
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On the last point, Emilio has informed me that root content documents are deliberately opaque by default. However, we support a `transparent="true"` field on `<xul:browser>`s, so perhaps geckoview could add an API which allows an embedder to opt in to using that.