Extend AppCompatSpinner in SelectionModificationSpinner

app/src/main/java/org/transdroid/core/gui/navigation/SelectionModificationSpinner.java

@@ -20,9 +20,10 @@ import android.content.Context;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ArrayAdapter;
-import android.widget.Spinner;
 import android.widget.TextView;
 
+import androidx.appcompat.widget.AppCompatSpinner;
+
 import org.transdroid.R;
 
 /**
@@ -31,7 +32,7 @@ import org.transdroid.R;
  *
  * @author Eric Kok
  */
-public class SelectionModificationSpinner extends Spinner {
+public class SelectionModificationSpinner extends AppCompatSpinner {
 
     private SelectionDropDownAdapter selectionAdapter;
     private OnModificationActionSelectedListener onModificationActionSelected = null;