My app is using the Support Library for compatibility on versions as low as Android 2.2 so I have to define my own XML namespace and use that namespace as the attribute prefix
Solution was this, I was writing this android:showAsAction="ifRoom"
but I should have app:showAsAction="ifRoom"
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
android:id="@+id/action_refresh"
android:icon="@drawable/ic_action_refresh"
app:showAsAction="ifRoom"
android:title="@string/action_refresh" />
<item
android:id="@+id/action_search"
android:icon="@drawable/ic_action_search"
app:showAsAction="ifRoom"
android:title="@string/action_search" />
<item
android:id="@+id/action_settings"
android:title="@string/action_settings"
app:showAsAction="never" />
</menu>