Redmine

I'm new to Redmine and would like to connect an issue in one of my subprojects to a file located in the parent project's repository.

I've tried the source:repo_identifier|some/file format, but it only creates a link if the issue is created in the parent project. In the subproject it just shows up as plain text. I have "Allow issues of all the other projects to be referenced and fixed" enabled, but it doesn't seem to do anything for what I'm trying.

Am I missing a setting that would allow for a subproject to reference a parent's repo? I'm running Redmine 2.3.2.