When I open the burner in a web3-less browser, the Advanced page shows three buttons: "Show PK", "Copy PK" and "Hide PK". If I open the burner in a browser with MetaMask enabled, the same page shows up as empty. <img width="1680" alt="Screen Shot 2019-09-28 at 20 01 22" src="https://user-images.githubusercontent.com/8782666/65833377-8729fd00-e2d8-11e9-9099-c42a89c8ddbb.png"> Ideally, there would be no "Advanced" button when web3 is injected - and perhaps a hint that you should switch to "dai.poa.network" would help.