The new editor does not properly create links that do not use one of the standard web protocols when inserting with the Insert Link dialog (e.g. http://, ftp://). It creates the <a> but without a href attribute. In 3.5 and earlier, you could create a link for any protocol type using wiki markup: [something://mysite.com]. Inserting the wiki markup results in the link being stripped and the URI appearing as plaintext.

The only workaround is to insert a link manually with the HTML macro, but not all sites will be able to enable this macro for security reasons.

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The fix in 4.3.7 allows non-standard protocols, but not if they have numbers in the protocol.

e.g. exp://Ticket/12345 works fine but exp2://Ticket/12345 is not rendered as a link.