Getting a 404 on mixins.js

First of all, thank you for this great tool.I'm using the latest version.The bug happens with a local copy of GrapesJS.MacOS - latest Chrome browserThe bug is not present on the demoExpected behavior: have the editor loading without any errorsWhat happens instead: I get a 404 error when the editor is appending styles I'm getting the following error on the console after the editor is started: mixins.js:27 GET http://example.com/editor/null net::ERR_ABORTED 404 (Not Found) I replaced the real domain with "example.com", the rest of the URL is real. On mixins.js, line 27, the instruction is head....