Getting "Split Screen or picture-in-picture is not supported for this app"

I am trying to support split screen feature in my app.

Target SDK is 27 currently

 defaultConfig {
        applicationId "com.myvestige.vestigedeal"
        minSdkVersion 19
        targetSdkVersion 27
        versionCode 46
        versionName "5.5"
        multiDexEnabled true
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

and added resizeableActivity to "true" inside manifest in application tag.

<application
        android:name=".activity.MyApplication"
        android:allowBackup="false"
        android:icon="@drawable/newicon1"
        android:label="@string/app_name"
        android:largeHeap="true"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:replace="android:icon"
        android:resizeableActivity="true">

Still when I am sliding down with three fingers(manual screen-split), getting "Split Screen or picture-in-picture is not supported for this app".

Also attaching screenshots of error message I'm getting. I am using vivo-v9(8.1.0) for the testing purpose which supports split screen.

Please help me in finding what I'm doing wrong.

Thanks

Finally I am able to find the solution of the problem. Split feature working perfectly in other devices(tested in Oppo F3, One plus 6 and Samsung j8) but not working in Vivo v9. I have reported the same to Vivo support team and they replied as

"Kindly go to setting > smart split > it will work only those application which are showing there. I do understand your concern, but it will work on those application which is showing there."

Apps listed inside setting > smart split > in Vivo v9 are Facebook, Whatsapp, Gamil etc... I am also attaching screenshots of the apps listed there