It adds time to create your label and then close that box and then click on the Label to enable and disable labels. I think it would be great to have the option to enable and disable labels within the Labeling Properties box.
If you're using Pro it's easy to toggle on the labels in the Labeling view of the contents pane. see the video below where I've set up the labels and then real quick turned on the labeling by checking the box next to the layer name.
