title: How to upgrade MvxFragmentAttribute
body: <p>I'm updating my project to MvvmCross 6.0 from 4.3</p>
  
  <p>The MvxFragmentAttribute is gone and seems to have been replaced by MvxFragmentPresentationAttribute</p>
  
  <p>However when using the new Attribute I get the following error:</p>
  
  <pre><code>System.NullReferenceException: FrameLayout to show Fragment not found
  at MvvmCross.Droid.Support.V7.AppCompat.MvxAppCompatViewPresenter.ShowFragment (System.Type view, MvvmCross.Platforms.Android.Presenters.Attributes.MvxFragmentPresentationAttribute attribute, MvvmCross.ViewModels.MvxViewModelRequest request) [0x00090] in &lt;8141cf24d04c4cc6ba0be8d85f7b3f82&gt;:0 
  at MvvmCross.Platforms.Android.Presenters.MvxAndroidViewPresenter.&lt;RegisterAttributeTypes&gt;b__21_2 (System.Type view, MvvmCross.Presenters.Attributes.MvxBasePresentationAttribute attribute, MvvmCross.ViewModels.MvxViewModelRequest request) [0x00000] in &lt;17df0d0bdae848b7a8a12b58d710f763&gt;:0 
  at MvvmCross.Platforms.Android.Presenters.MvxAndroidViewPresenter.Show (MvvmCross.ViewModels.MvxViewModelRequest request) [0x00014] in &lt;17df0d0bdae848b7a8a12b58d710f763&gt;:0 
  at MvvmCross.Platforms.Android.Views.MvxAndroidViewDispatcher+&lt;&gt;c__DisplayClass2_0.&lt;ShowViewModel&gt;b__0 () [0x00000] in &lt;17df0d0bdae848b7a8a12b58d710f763&gt;:0 
  at MvvmCross.Base.MvxMainThreadAsyncDispatcher+&lt;&gt;c__DisplayClass0_0.&lt;ExecuteOnMainThreadAsync&gt;b__0 () [0x00000] in &lt;17df0d0bdae848b7a8a12b58d710f763&gt;:0 
  at MvvmCross.Base.MvxMainThreadAsyncDispatcher+&lt;&gt;c__DisplayClass1_0+&lt;&lt;ExecuteOnMainThreadAsync&gt;b__0&gt;d.MoveNext () [0x00011] in &lt;17df0d0bdae848b7a8a12b58d710f763&gt;:0 
  --- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in &lt;f32579baafc1404fa37ba3ec1abdc0bd&gt;:0 
  at System.Runtime.CompilerServices.AsyncMethodBuilderCore+&lt;&gt;c.&lt;ThrowAsync&gt;b__6_0 (System.Object state) [0x00000] in &lt;f32579baafc1404fa37ba3ec1abdc0bd&gt;:0 
  at Android.App.SyncContext+&lt;&gt;c__DisplayClass2_0.&lt;Post&gt;b__0 () [0x00000] in &lt;263adecfa58f4c449f1ff56156d886fd&gt;:0 
  at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in &lt;263adecfa58f4c449f1ff56156d886fd&gt;:0 
  at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00008] in &lt;263adecfa58f4c449f1ff56156d886fd&gt;:0 
  at (wrapper dynamic-method) System.Object.515beccd-4ae3-42be-a59f-9c8897c1459b(intptr,intptr)
  </code></pre>
  
  <p>Unfortunately this does not tell me which FrameLayout or even which Fragment and the stack trace contains none of my code.</p>
  
  <p>However only one of the Fragments has been hit before this happens:</p>
  
  <p>Old Attribute usage:</p>
  
  <pre><code>[MvxFragment(typeof(MainViewModel), Resource.Id.main_frame_layout)]
  </code></pre>
  
  <p>New Attribute usage:</p>
  
  <pre><code>[MvxFragmentPresentation(typeof(MainViewModel), Resource.Id.main_frame_layout)]
  </code></pre>
  
  <p>And yes main_frame_layout does exist in my main_view layout which is as follows:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:local="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/main_draw_layout"
      android:fitsSystemWindows="true"&gt;
      &lt;android.support.design.widget.CoordinatorLayout
          android:layout_width="match_parent"
          android:layout_height="match_parent"&gt;
          &lt;FrameLayout
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:id="@+id/main_frame_layout"
              android:layout_centerInParent="true" /&gt;
      &lt;/android.support.design.widget.CoordinatorLayout&gt;
      &lt;FrameLayout
          android:layout_width="wrap_content"
          android:layout_height="match_parent"
          android:layout_gravity="left|start"
          android:id="@+id/main_navigation_layout" /&gt;
  &lt;/android.support.v4.widget.DrawerLayout&gt;
  </code></pre>