Nodes UI does not work correctly when [POST] /rest/nodes/config is used

[jrobble]

I had the Nodes UI open, submitted new JSON to [POST] /rest/nodes/config, and immediately saw the spare node and services in the Nodes UI. The problem is that if you add/remove a service/node through the UI without first refreshing the page, then the change will be applied to the old node configuration stored in browser memory, which does not reflect the changes you just POSTED. For example, after the spare node was added, I removed a service on a core node using the UI, and then the spare node disappeared.