This attachment contains the wireshark capture of the described behaviour. It starts just before the upload button is pressed. It contains the upload, first carousel button press (incorrect response), and second carousel button press (correct response).

javax.faces.ViewState is missing from the carousel post that does not work, resulting in a full page update.

The carousel issue is fixed, but other components may have the same problem:

writeJavascriptFile() is being called and optionally rendering the script and the outer span. If the script is not rendered, writeJavascriptFile decides also not to render the outer span, resulting in a large DOM update.

If many components already manage an outer span with writeJavascriptFile() inside it, then this should be left as-is and components should be modified to ensure that the span is always rendered. However, if the component renderers do not generally manage this span or do not have multiple JavaScript files together, writeJavascriptFile() should be modified to always render the span and then test whether to render the script or not.

This specific issue is no longer observed. If a different JavaScript technique is chosen for various components, this should be done under new JIRAs for a future release.