android - Puzzling behavior with REORDER_TO_FRONT

Question

Activity A starts activity B with no flags. The stack is now A-B with B on top. B starts activity A with FLAG_ACTIVITY_REORDER_TO_FRONT (the only flag). I would expect the stack to now be B-A. However, when the back button is pressed at this point it returns to the home screen. Here I would expect Activity B to be brought to the front. Upon clicking on the launcher icon again, the app opens with B as the running activity and nothing in the stack.

Launchmode is standard (default) in the manifest.

Is this the expected behavior and I'm just not understanding it properly?

EDIT: I have created a test project with no confounding factors and still see the same behavior. I just don't understand it, it doesn't seem to be per the documentation.

EDIT: To me this behavior seems to be a BUG in the framework, see my comment on answer below. I need a workaround.

public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); }

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}
public void onClickBtn(View view)
{
    Intent flowIntent = new Intent(this, SecondActivity.class);
    startActivity(flowIntent);
}

}

public class SecondActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); }

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}
public void onClickBtn(View view)
{
    Intent flowIntent = new Intent(this, MainActivity.class);
    flowIntent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
    startActivity(flowIntent);

}

}

Manifest: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android&quot; package="com.example.tester" android:versionCode="1" android:versionName="1.0" > <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="18" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="com.example.tester.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name="com.example.tester.SecondActivity" /> </application> </manifest>

Answer 1

http://code.google.com/p/android/issues/detail?id=63570#c2

it had been confirmed by google as a bug on 4.4.2