The Icons will go gray (stale) when vFoglight Storage does not have the last 3 polling periods of information.
If you have just installed the application it will take a little while to populate this information.
If you have been running awhile there are some other places you should look.
1) Did you set up a collection schedule? The schedule needs to be configured, applied, and activated. If all 3 are not done it will not collect.
You should also note the blackout period since it will not collect during this time. The blackout period is based on the time on the server so be sure you know what time it is.
2) When you look at the Data Collection setup for the device that is gray, you can see if it is getting current information. Here is what it will look like under normal circumstances:

Check for 3 green dots, and a current timestamp next to each one. If the perf? Does not have a current timestamp or not a green dot, this is why your icon is stale.

Same thing happens with me also. The vcenter shows green but the datacenters/datastores/esx hosts within the vcenter show as stale.

If you look at the Data Collection does it show it is collecting? Current timestamp?

The datacollection for the vcenter shows as collecting. The last run time was less than 10 minutes ago.