The Shortcuts thing is ok but I started looking around the source code and by referencing the
Commits since 4 weeks back I was able to find out where the Themes menu was (apps\menus\theme-menu.c,
) and started messing around with a single line.
I started messing around with this line (currently line 172):
static struct browse_folder_info themes = {THEME_DIR, SHOW_CFG};
and after a few tries changed it into this:
static struct browse_folder_info themes = {THEME_DIR, ""};
It does exactly what I wanted it to do now, the Browse Themes menu displays folders. At compilation it displays a small error but it still works though.
Thanks to everyone in this thread for there help, Jonathan Gordon for putting together the Themes menu and all the Rockbox developers for making the code so flexible and easy to read.