Solved problem with my menu and submenu

Good morning,

I have a problem with my menu.
When I click on the menu item: https://www.wildnisteam.de/wt-kursuebersicht/
move the mouse, 3 sub-items popped up.

Now the problem:
If I move the mouse over the menu item Children, a submenu opens. If I want to select something there now, it disappears. I can't select anything.

Why is that?

In the DIVI support center under Safe Mode I switch it on and my menu behaves completely differently.

Thank you for your help.

 

Thies CSS-Code help:

#top-menu li li {
width: 100%;
}