Whenever you want to temporarily disable the symbology in a layer, but still want the layer active for the labels, there should be a "Symbolize features in this layer" button, like the "label features in this layer" button.
Maybe there already exists some other easy way to achieve this? but it seems to make the most sense to me to have an option completely similar to the "label features in this layer" button, rather than having one method for symbology and another for labels.
