Michael: Thank you very much, that's how I understand it. If there is someone who can do the icon placement for the white theme in the menu builder, also in the topbar, I will thank you.

Well,
even if you have no idea of programming as you were often pointing out, it can't be so hard to understand that dynamically expanding a VERTICAL menu by new entries - and that's what the Menubuilder actually does - doesn't need any extra care, because your members simply can scroll down the page a in case the menu becomes larger than the screen. Expanding a HORIZONTAL menu is a true challenge compared to that. It's: how to arrange these new entries if there's no more space available? On a new line? With a horizontal scrollbar? All in all it would need a lot of extra calculations, just in order to keep the original shape of the theme on one hand, while having any number of new clickable items arranged in an unconfusing way on the other.

Michael:
There is such an ingredient, you just have to add that little addition. It's called Menu Builder. In addition, I use a white theme.

I think if there's a component that does just that ...

Yes, but currently there's no such component, so you should think of hiring a developer to do the job for you.

I think if there's a component that does just that, it's much easier to add another line to put it in the topbar as well, not just where it's already listed in the component's menu.

I don't know how to program, if I were a programmer, the task would have been completed a long time ago.

The recurring question "(How) can it be solved?" question has already been answered umpteen times here in the forum: Yes, by developing a component that replaces, extends, changes, or deletes existing properties/features of Ossn. As in this case the topbar element of your theme and in your other thread the font-size of the chat. See
https://www.opensource-socialnetwork.org/wiki/view/704/should-i-modify-core-files

Example