grapes.min.js:2 Uncaught TypeError: Cannot read property 'length' of undefined

Thanks for the report, the fix is ready for the next release.

I am encountering a similar issue with v0.19.5 when I try to add an iframe inside of a custom code block

TypeError: m.render is not a function
    at a.value (ComponentsView.js:86:23)
    at a.value (ComponentsView.js:39:10)
    at y (backbone.js:371:57)
    at m (backbone.js:356:19)
    at h (backbone.js:155:16)
    at u.trigger (backbone.js:346:5)
    at n._onModelEvent (backbone.js:1187:20)
    at y (backbone.js:372:58)
    at m (backbone.js:357:22)
    at h (backbone.js:155:16) {level: 'error'}