code: protected void applyDrawerWithHeader() {
          setType(SideNavType.DRAWER_WITH_HEADER);
          applyBodyScroll();
  
          if (isShowOnAttach()) {
              Scheduler.get().scheduleDeferred(() -> {
                  pushElement(getHeader(), 0);
                  pushElement(getMain(), 0);
              });
          }
      }
docs: Provides an overlay / drawer sidenav that will float on top of the content not the navbar without
  any grey overlay behind it.