I just updated with the latest dev branch and my applications toolbar icons are no longer showing. So in time honoured fashion I checked the demo and also found issues there. Note, that I can only check this on Linux for the time being.
If you launch the Demo and navigate to the toolbar demo everything works fine. Then open the System info pages, and scroll down. Go back to the toolbar demo and many of the icons are now gone. For clarity sake, here’s a gif