A lot requests sent, when Dashboard widget Refresh interval set to "No refresh".

Steps to reproduce: 

1) Create new Dashboard

2) Add widget "Map navigation tree" (you can add any widget)

3) Save dashboard.

4) Click on widget and change Refresh interval to - No refresh. 

5) Refresh page (press F5)

6) In browser press F12->Network (checked in Chrome). 

Result: 

A lot of requests sent. 

Screenshot:

GIF:

Expected: 

not sure... Nothing?