Thanks for the link, I had not found that myself and the workaround suggested (installing the Unity integration module for GTK) worked! It generates a spurious error message about Unity not being on the machine, but that's way less annoying than a 25 second pause on startup.
https://forum.lazarus.freepascal.org/index.php/topic,51016.0...
I have not seen it, but it would affect all my programs, it sounds very annoying