Firefox PicLens plugin causes slow performance of Confluence
This problem is related to a third party plugin, and therefore not supported by Atlassian. See Atlassian Supported Plugins for more information.
Unusually slow performance from Confluence and response time for requests. This is a browser-specific issue.
Customer found that the PicLens add-on for Firefox was causing this problem.
Disabling the PicLens add-on restored performance.