Jennifer Mourek 3a8ba39abd Disable auto-refresh when page is not visible
credits to @towolf

Icinga offers the user to enable or disable 'auto-refresh' with a
static preference.

But 'auto-refresh' is the default and our users often have dozens of
Icinga tabs open in their browser, which they are not looking at.

The background tabs lead to significant load on the database to to
repeated queries to keep the invisible UI fresh.

This change adds a visibility listener, which disables auto-refresh when the
page is not visible.

refs #2761
2017-10-26 13:53:25 +02:00
..