title: How to disable Hamburger Icon turnung into arrrow (Navigation Component)
body: <p>Help me out please.<br>
  <strong>Intro</strong>: I use Navigation Component, Single Activity pattern with 3 fragments switched via bottom navigation menu. Also I have Drawer Navigation.<br>
  All fragments are of the same level (all are root, accessed directly from bottm nav)<br>
  <strong>How things should be</strong>: For all fragments there must be a toolbar with hamburger icon for the drawer.<br>
  <strong>Problem</strong>: when app starts, the home fragment shows standard hamburger icon for drawer, which is ok. But when I switch to any other fragment, the drawer icon turns into arrow icon. 
  Furthermore, when ths arrow is pressed, the drawer slides from left. It means <strong><em>it still works as a button for showing the Drawer menu, but only icon changed</em></strong>.<br>
  <strong>Question</strong>: How can I disable transformation of hamburger icon into arrow icon when switching to another fragments from bottom navigation menu?<br>
  <strong>Files</strong>:
  Navigation Graph:  </p>
  
  <pre><code>&lt;navigation xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      android:id="@+id/nav_graph"
      app:startDestination="@id/bottom_nav_proposals"
      &gt;
      &lt;fragment
          android:id="@id/bottom_nav_proposals"
          android:name="com.base.ProposalsContainerFragment"
          android:label="fragment_proposals"
          tools:layout="@layout/fragment_proposals" /&gt;
      &lt;fragment
          android:id="@id/bottom_nav_vehicles"
          android:name="com.base..DriversVehiclesFragment"
          android:label="Vehicles" &gt;
      &lt;/fragment&gt;
      &lt;fragment
          android:id="@id/bottom_nav_drivers"
          android:name="com.bijov1apps.base.carrier.root.drivers.DriversVehiclesFragment"
          android:label="Drivers" &gt;
      &lt;/fragment&gt;
  &lt;/navigation&gt;
  </code></pre>
  
  <p>Activity:  </p>
  
  <pre><code>    override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
  //initializing Navigation COmponent
         val navHostFragment = supportFragmentManager.findFragmentById(R.id.nav_host_carrier_root) as NavHostFragment
          val navController = navHostFragment.navController
  //setting up toobar stuff
          val toolbar: Toolbar = findViewById(R.id.toolbar_root)
          toolbar.setupWithNavController(navController, drawerLayout)
  //setting up navigation drawer stuff
          val drawerLayout:DrawerLayout = findViewById(R.id.drawer_layout)
          val navView: NavigationView = findViewById(R.id.nav_view)
          val toggle = ActionBarDrawerToggle(
              this, drawerLayout, toolbar, R.string.navigation_drawer_open, 
          R.string.navigation_drawer_close
          )
          drawerLayout.addDrawerListener(toggle)
          toggle.syncState()
          navView.setNavigationItemSelectedListener(this)
  //setting up bottom navigation menu stuff
          val bottomNavigationView = findViewById&lt;BottomNavigationView&gt;(R.id.logisticBottomBar)
          bottomNavigationView.setupWithNavController(navController)
  }
  </code></pre>