Caused by: java.lang.ClassCastException: android.support.v7.widget.AppCompatImageView cannot be cast to de.mrapp.android.util.view.ElevationShadowView
    at de.mrapp.android.preference.activity.PreferenceActivity.showButtonBar(PreferenceActivity.java:1863)
    at de.mrapp.android.preference.activity.PreferenceActivity.handleShowButtonBarIntent(PreferenceActivity.java:471)
    at de.mrapp.android.preference.activity.PreferenceActivity.onFragmentCreated(PreferenceActivity.java:2387)
    at de.mrapp.android.preference.activity.fragment.PreferenceHeaderFragment.notifyFragmentCreated(PreferenceHeaderFragment.java:64)
    at de.mrapp.android.preference.activity.fragment.PreferenceHeaderFragment.onActivityCreated(PreferenceHeaderFragment.java:127)
    at android.app.Fragment.performActivityCreated(Fragment.java:2061)
    at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:912)
    at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
    at android.app.BackStackRecord.run(BackStackRecord.java:834)
    at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1452)
    at android.app.Activity.performStart(Activity.java:6005)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2320)
    ... 10 more