Unconditional stylesheet output in backend leads to incompatibility with other plugins

[Dherlou]

Problem

The unconditional style output at the end of the backend plugin.php leads to an incompatibility with other plugins like Seans QR Code Plugin. This happens, because the QR Code Plugin displays the QR Codes directly as images with Header("Content-type: image/png");and the unconditional output of this plugin (<style>ul#admin_menu li:not(.frontend_link) {display: none}</style>) destroys the output, which leads to a corrupt image.

Solution

The style definition should only be loaded on required pages with the help of yourls hooks.