New Relic’s Real User Monitoring (RUM) breaks the EPiServer’s File Manager in Edit Mode
Update: There is a hotfix available for this, see Per’s comment further down. We noticed a weird problem on one of our test servers in my current project some time ago. For some reason there was a massive output of JavaScript in the EPiServer ActionWindow, in addition to the normal functionality making it impossible to use the file manager. Us not experiencing anything like it …