Previewer in presets window of a plugin

Hi, curious to know why the previewer in the presets window of a plugin is not doing something in my setup.

While inside the mediaBay I get previews as expected, when in the plugin browser’s similar window, there’s no preview, and at the same time, when I select a preset, it automatically replaces the previous one in the slot. This one is great actually, but adds to my curiosity about what is the functionality of the previewer in this window.

I’m talking about this one: