Don't know if this is a Webkit or a V8 bug. A chromium developer proposed the usage of sandboxed iframes for disabled scripting in designmode documents. Doing so with the attribute sandbox="allow-same-origin", which should give us the same result like in all other browsers with designmode iframes, the contentWindow reference is absent. Is this a bug or a feature?
Could you please provide a test case or an URL of site where this problem occurs?
Created attachment 57377 [details] The testcase shows that the second iframe can't get designmode because it has no valid contentWindow pointer.
I cannot reproduce this with r60144 nightly, looks like a v8 issue.
After uninstalling/ reinstalling Safari the Webkit nightlys run on my PC. And i can confirm it's a Chromium issue. The Webkit issue is the not disabled form-elements. Without "allow-forms" the form should not submit. Maybe i file a extra bug for this.