After fixing #370 (closed) via !313 (merged), something that we noticed is that when the proxy is enabled with a local version of HedgeDoc (formerly CodiMD) we get a popup that we wouldn't normally get:

Unfortunately it's unclear if this is a bug, because it was reported in the past but this seems to appear only if are proxying the service.

We should try to investigate why this happens, as it might be masking other problems in the proxy itself.