Hey Jarook,

I am really sorry for the delay of this reply as it is a weekend for us here. This is not possible out of the box but you could add some custom css codes to make this happen,

[gist]
body.has-docker > nav.navbar {
position: fixed;
width: 100%;
top: 40px;
margin-top: 0 !important;
height: 52px !important;
z-index: 99;
}
[/gist]