I have created a drop down menu in my forums main navbar, with all the themes I have installed.
I want user to be able to change easily the forum theme.
I have seen this in other forum that is working simply with <a href="/forums/index.php?variant=lilac">Lilac</a>
Lilac = forum theme
but does not work in my case..
That only works if a) you have variants set up correctly (variants are different from full themes) and b) have configured the system to use it.
If you want full themes, you need to use theme=### not, variant