When reading an embedded media content video / audio from a bookmark with the embedded webview, the device screen goes into standby mode after a certain delay (defined in the android system).

The alternative to that is to let all links open in a browser directly, but then you loose the ability to highlight text on a bookmark. The third alternative which I use right know is to click on the bookmark and then on the browser link to open it on another browser. This works, but i's quite annoying!