title: Android recent activity displayed after intent filter activity is finished
body: <p>So my app has a problem with 2 activities - <code>MainActivity</code> and <code>ShareActivity</code>. As you might guess, the <code>MainActivity</code> is the main activity and does most of the work. <code>ShareActivity</code> has an intent filter for receiving files. When i share something from another app, the <code>ShareActivity</code> is launched and it does it's work (user has to pick a folder there) and finishes.</p>
  
  <p>If i just share something to my app, <code>ShareActivity</code> is launched, it does everything it should, it finishes and user is back in the app from which he shared the item. The problem is, if i have recently opened my app (<code>MainActivity</code> is in recent menu), when <code>ShareActivity</code> has done it's work and finishes itself, instead of showing the app from which user shared the item, <code>MainActivity</code> is displayed.</p>
  
  <pre><code>[Activity (
      Label = "Failiem.lv",
      NoHistory = true,
      ExcludeFromRecents = true,
      ScreenOrientation = Android.Content.PM.ScreenOrientation.Portrait
  ),
  IntentFilter (
      new[]{Intent.ActionSend, Intent.ActionSendMultiple},
      Categories = new[]{Intent.CategoryDefault, Intent.CategoryOpenable},
      DataMimeType = "*/*"
  )]
  public class ShareActivity {
      ...
  }
  
  
  [Activity (
      MainLauncher = true,
      Icon = "@mipmap/icon",
      WindowSoftInputMode = SoftInput.AdjustPan,
      ScreenOrientation = Android.Content.PM.ScreenOrientation.Portrait,          LaunchMode = Android.Content.PM.LaunchMode.SingleTask
  )]
  public class MainActivity {
      ...
  }
  </code></pre>