How does advertising in a dropdown list or menu work?

Question

contextual advertising

Hello! I was interested in two questions, how advertising, for example Yandex, will work if it is inserted into a drop-down list, a menu for a site or a user profile:
1. Will it be considered shown when the page for the user loads or when the user clicks on the menu or profile?
2. The second example: there is a category 1, it has a subcategory 1.1 and a subcategory 1.2. The user hovered over subcategory 1.1 - ad 1 was shown to him, hovered over subcategory 1.2 - ad 2 was shown to him.

Answer 1

Viewing ads will be counted according to the rules of the advertising network - at least 50% of the banner area within 1 (2) seconds.