change activity launch mode to singleInstance makes me lose my custom animation

Question

I change activity launch mode to singleInstance in AndroidManifest.xml

<activity
     android:name=".Photos"
     android:launchMode="singleInstance"
     android:label="Photos"
     android:theme="@style/AppTheme.NoActionBar" />

but it makes me lost my cutom animation in styles.xml

<style name="CustomActivityAnimation" parent="@android:style/Animation.Activity">
    <item name="android:activityOpenEnterAnimation">@anim/slide_in_right </item>
    <item name="android:activityOpenExitAnimation">@anim/slide_out_left </item>
    <item name="android:activityCloseEnterAnimation">@anim/slide_in_left</item>
    <item name="android:activityCloseExitAnimation">@anim/slide_out_right </item>
</style>

which has been working fine before adding android:launchMode="singleInstance" attribute to AndroidManifest.xml

any help please ?