pb-browse-docs: default browsernavigation not working as expected

[Bpolitycki]

pb-browse-docs implements an SPA-Style-Navigation – the page is not fully reloaded, content is fetched via the Publisher-API and inserted in the component, entries are pushed to the browser-history – but the default navigation via back (and also forward) button is not working as expected.

It seems like that the expression in line 132 in pb-load never evaluates to true, because ev.state is (in my first tests always) null or undefined.

From a UX perspective, it would be desirable if not only the control buttons of the component enabled navigation, but also the default options of the browser.