Media overlays playback on Safari, page reloads and playback stops

[CircularKen]

This issue is a Bug

Expected Behaviour
Readium is expected to play Media Overlays without stopping and without reloading page.

Observed behaviour
When first attempting to invoke the media overlays playback after a browser refresh, the page reloads and playback stops.

Steps to reproduce
Using Safari Version 11.0 (12604.1.38.1.7) on Mac OS 10.12.6 (16G29)
In Safari, using the Readium control bar you get click 1, bars goes dark, page reloads bar stops, click 2, bar darkens and playback starts.
And with the button on the page you get click 1, refresh, click 2, nothing, click 3 playback starts.
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In Chrome Version 61.0.3163.100 (Official Build) (64-bit) things are better. The overlays DO highlight as expected and although we still get the page reload the playback does continue so only requiring one click.

Product
Readium cloud reader app - latest development build uploaded at https://readium.firebaseapp.com

Additional information
There is a separate issue about overlays NOT highlighting that in Safari to see expected results, check the link using Chrome.

[danielweck]

The separate issue about Safari is in fact related to the browser engine itself, and can be reproduced outside of Readium when loading the HTML document on its own.

[CircularKen]

Confirmed. The separate issue about Safari is related to functionality that is missing in later versions of Safari so not a Readium issue. FYI Version 10.0.3 of Safari functions as expected.

[danielweck]

Thank you for reporting the issue about EPUB3 Media Overlays playback (i.e. unnecessary reloading of fixed-layout "pages" when transitioning from one to the next in a two-page spread). This is due to the fact that FXL "pages" are actually independent spine items, loaded in their respective iframe, on the left and right side of the two-page spread. This behaviour should indeed be corrected (to avoid the irritating content flash / flicker), but as it stands now the refresh is necessary due to some internal changes in the underlying document layout/rendering architecture.
As per your bug report, there may in fact be an additional issue with respect to Media Overlays playback stopping instead of automatically continuing into the next "pages". To be investigated...