Graph widget goes into infinite loading after removing an item.
Not reproducible each time!

Steps to reproduce:

1. Create a new Graph widget.
2. Add several items.
3. Wait for some time.
4. Remove/add one of the items.

Actual result:

The Graph widget shows an infinite loading state. No errors are displayed in the browser console or in logs.
After saving the dashboard, the graph is displayed correctly.

Expected result:
The Graph widget should refresh correctly after an item is removed.