This problem has been vexing me all day as well; I'm glad I'm not the only one.
I can't get this to work even if I change the default value of WEBUI_PORT. I'm beginning to suspect there is something odd in this particular Docker image that is forcing all Unraid WebUI GUI links to the default IP:8080 regardless of the link specified in the Advanced view of the Docker configuration page.
My goal: Multiple instances of binhex-qbittorrentvpn, each using a different port for their respective WEBUIs.
I can get the WebUI to be active on a non-default port by doing the following:
1. Delete Host Port 3 (default 8080:8080)
2. Add new TCP mapping [newport]:[newport]
3. Change WEBUI_PORT to [newport]
But regardless of what I change in the WebUI field (Unraid advanced view), the Unraid GUI link redirects me to IP:8080. The only exception is if I manually map container port 8080 to [new port], in which case I get linked to IP:[new port]. But since the container requires a [newport]:[newport] mapping for the WebUI to function, I can't add a second mapping of 8080:[new port] to force the link in the Unraid GUI to work properly.
The field just doesn't seem to change even if I hard code the WebUI link to http://[IP]:[newport] or change it to http://google.com. Other containers let me change the WebUI link to literally anything I want, which leads me to believe this has something to do with this specific container. I can't find anything in the dockerMan XML file referencing port 8080 so it's got to be somewhere deeper.
Yes I could just bookmark the individual links and never access them via the Unraid Docker page, but it would really be nice to have so that in the future I don't have to reinvent the wheel if I ever lose track of which ports I used.
I'd love to help troubleshoot this because I'm at my wit's end trying to get this to work and am pretty close to giving up and just using binhex-rtorrentvpn.