How cms bitrix determines the height of the catalog menu?

Question

PHP

There is a catalog menu, if there are too many categories, then a part is hidden and 3 dots are displayed.
How in this case does Bitrix determine the number of points to be withdrawn? the screenshot shows that the catalog should be reduced by a couple of points. here is the question, how to do it?

Answer 1

I think Bitrix has nothing to do with it, most likely some kind of JS is working here.

Answer 2

it is unlikely that anyone will be able to understand something from the picture!
You should at least see the link.