Update frequency in Top Hosts (Local) and other places

I observe several problems, but I think they can actually be related. 
I'd like ntopng to auto-update information in browser only once per 
minute, since more frequent updates are meaningless with ASA flows. I 
set all periods I found in preferences to multiples of 1 minute. 
However, I noticed that browser still polls server every second or so, 
causing unnecessary load on both server and client systems.

It'd be nice to fix it for all windows, but problem is especially awful 
on Top Hosts (Local) page, since:

1. The chart is filled with empty values making it essentially unusable:
https://rqc.box.com/s/6azwv13vkzqjkajjusvcmw5owkexfahm

2. Looks like each top host is queried with a separate request, causing 
huge CPU load (dozens of request per second in place of one per minute 
necessary).

Is there some setting for this I'm missing, or is it a current limitation?


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With Best Regards,
Marat Khalili