問題

Workbox notification icon  (introduced in Confluence version 4.3) is not displaying when using Chrome and having the Do Not Track Plus Chrome extension enabled.

原因

The corresponding extension is made to avoid websites track you. Apparently it recognizes the workbox notification icon as a potential risk.

回避策

Disabling the extension solves the issue, however adding the Confluence site to its whitelist might be a considerable option, but in some cases this does not fix the issue.