LibreArp cannot save presets

LibreArp has save / load presets buttons that works in standalone, and also in others DAWS, but not in Ardour. Any idea of what is going wrong ?

Does it work using Ardour’s Plugin Presents?

When you use it as standalone, does the plugin open a dedicated File Selector Window?
If so, it needs x11: update the file dialog to use vfork, and not require quoting · steinbergmedia/vstgui@49b87d8 · GitHub and a you can find a workaround: File browser windows not opening in plugins - #2 by x42