All changes that are done under the Configuration tab are saved in a working copy that is stored in your current browser session. This enables you to make multiple changes before you deploy it as your running configuration. You can also use live staging to test your new configuration or, for example, compare the working copy with another revision.
To deploy your working copy, go to Configuration -> Deploy (top right), enter a message, and click on the Deploy button. The working copy has now become the running copy, and will be automatically pushed to all the other nodes in your cluster.