I have a custom toolbar with one item on it, "Favorites *MyFavs1".
This shows all my favorites within favorites subfolder MyFavs1.
When I want to add a new directory location to that toolbar, I have to rightclick on the dir name, select add to favorites, open Edit Favorites, then move the new entry to subfolder MyFavs1 and finally it appears on my toolbar.
It shore would be nice to simply drag the directory name from the explorer window and drop it on that toolbar. Done!
ps. in case someone wonders, I use favorite subfolders as I actually have several toolbars showing different favorite subfolders MyFavs1/2/3 etc.