Question: I run this program and after that i get "Errors exists do you want to continue". Then i click yes and i get "Hello world" in the console. Which was the project i ran previously. 
Anybody knows what is the problem? 

```
#include <iostream>
#include <typeinfo>
using namespace std;

int func() {
    return 42;
}

int main ( int argc, char ** argv ) {
    auto x = func();
    cout << x << endl;
    cout << typeid(x).name() << endl;
    return 0;
}

```

Answer: 
Add this to your css file:

```
header {
    z-index: 100; 
}

```

> 
> The z-index property specifies the stack order of an element.
> 
> 
> An element with greater stack order is always in front of an element with a lower stack order.
> 
> 
> Note: z-index only works on positioned elements (position:absolute, position:relative, or position:fixed).
> 
> 
>
Additional question about the same site. When scrolling through the site, the menu-item should change with every slide it passes. At this moment the last clicked menu-item is highlighted, even when scrolling through to the several slides. Is there an easy way to make that work in CSS? Or would that be possible by just adding a *jQuery.nav.js* to the *index.html*?