Header goes on a textbox

Hello, so first thanks to have create GrapesJs this very usefull. I have an issue i add an header on my page and that's the code i add for the header: <header style="padding: 100px 0px;position: absolute;top:0; width:100%"></header> The problem is : When i add first a text area or an other element and then i add the header both superimposed :

So can you answer with the property i have to manage. I want when i insert the header, the other elements go under. @artf