Failed to load help file issue

[expxiaoli]

This plugin can not work for me. I am not sure it is due to my jenkins incorrect configuration or plugin bug. So I do some investigation:

I check jenkins configuration page, and find this issue in "Global HipChat Notifier Settings". When I click "?" icon, it displays this alert info "ERROR: Failed to load help file: Not Found". Then I use chrome developer tool to catch more info, and find:
GET http://10.128.5.136:8888/jenkins/jenkins/plugin/hipchat/help-globalConfig-hipChatBuildServerUrl.html 404 (Not Found)
This http request is send when I click "?" icon. but the url path is incorrect, which should be:
http://10.128.5.136:8888/jenkins/plugin/hipchat/help-globalConfig-hipChatBuildServerUrl.html

Here is image to show above issue:

My jenkins url is http://10.128.5.136:8888/jenkins

Then I find similar issue in other jenkins plugin: https://issues.jenkins-ci.org/browse/JENKINS-12433
This issue happens when jenkins url is NOT root url.

So I guess it may be a plugin bug.