Usability Issue : No indication data is loading/refreshing

[chrism75671929]

When dragging in additional metrics, there is no visual indicator to suggest that the data is refreshing/loading.  Although there is some text, it is not very obvious- there should be a spinner or something along those lines.

[beju_ana]

I`ve the same problem

[BenjaminGaines]

I think I agree that this should be clearer. We definitely don't want to do anything that prevents you from continuing to interact with a panel while data is loading, but there are two ways to know:

1. In the title bar for a table, it should say "Retrieving data."
2. A cell that is involved in a running query should have a little yellow indicator in the upper-right corner. 

Hopefully that will help for now while we look at ways to improve this.