The discussion revolves around the deprecated Discourse Custom Topic Button plugin, which adds a customizable button at the bottom of topics for logged-in users. The plugin is now superseded by the official Topic Footer Buttons theme component, available at meta.discourse.org. Users can configure the button’s URL, title, and label via site settings. A key issue raised is that the button opens links in a new window, and users are seeking a way to open them in the same window. The plugin and theme component both use code that forces a new window, and while no UI option exists to change this, one user has offered to investigate a fix. The original plugin is hosted on GitHub, and installation instructions are provided via the official plugin guide. techAPJ notes the deprecation, while JammyDodger and Canapin discuss the technical limitations and potential fixes. danielabc requests the feature and praises the plugin’s functionality.
It does not seem that there’s currently a way through the UI to change that. It may be possible to amend that behaviour with a bit of custom work, but I’m afraid that’s not my forte.