Hamburger Menu Expanded inside BSS

Is there any way to expand hamburger menu inside BSS or its available only in preview?

In the app just add the class "in" to the div with the class of "navbar-collapse".

This <div class="collapse navbar-collapse" id="navcol-1"> to this <div class="collapse navbar-collapse in" id="navcol-1">

I just tried it myself and it works. It is not the same as being able to click the hamburger button because that requires Javascript to run/work within the app and it won't.