Rene,
You have paid for a commercial theme and so long as you are happy with the support they are providing that is what matters, really.
My comments were really aimed at determining whether the theme was based on BS2 or 3 and the history of the theme comes into that - and I do recall Julien being quite frustrated at the time.
But for complete transparency - Open Source software is there to be shared and the work done by one developer is often used by others and can, under the GPL licence, then be charged for. My own themes often take the work of others to bring several features together into a single theme. I have nothing against repurposing and reusing work released under the GPL -
providing it is properly credited. And that is one of the areas that some of the commercial themes, including the original form of this one, fall down on. I hope that has been corrected over the last few years, along with whatever else they have done to develop the theme along its own lines, which obviously make it suited to your needs.
From my comments and Gareth's response, it would appear that the theme is a mash up of both BS2 and 3 and that gives me some cause for concern for the users of the theme, but that is for the theme developers to deal with and support as with any commercial, paid for release, along with your bug that seems to be that the customcss is not being applied, thanks to Gareth's investigations.
Edit:
References to previous discussions:
https://moodle.org/mod/forum/discuss.php?d=259337#p1124717https://moodle.org/mod/forum/discuss.php?d=256900