Page Visibility

I've searched through the mailing list and read the API spec but I cannot
seem to find an answer. Apologies if this is not the best place to ask.

Regarding the Page Visibility spec. It seems that a document's
visibilityState is changed to hidden when the browser itself is moved to
the background. I'm curious to know the argument for this. Is it because
there is no way to determine if the browser is entirely hidden or just
partially?

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Brian Cardarella
CEO of DockYard
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