ActionBar menu Changed it's behavior after I changed inheritance from Activity to AppCompatActivity

Question

I took an older project of mine and imported it into Android Studio. As part of it, I had to change inheritance from Activity to AppCompetActivity to support ActionBar with its new API.

Now I have an unexpected behavior as a result: All menu items are flattened instead of being hidden behind the three dots menu icon like so:

Inheriting from Activity:

Inheriting from AppCompatActivity:

Any Idea?

Edited:

Here is my menu.xml:

Answer 1

Need to update namespace android:showAsAction to app:showAsAction attribute. Use the following code:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:orderInCategory="100"
        android:title="Menu Item 1"
        app:showAsAction="never" />

    <item
        android:orderInCategory="100"
        android:title="Menu Item 2"
        app:showAsAction="never" />
</menu>