Nullpointer when using custom adapter in the actionbar list menu (with the compat-v7)

I'm facing a Nullpointer exception when using the latest version of the compatibility lib (namely, v18 of compat-lib, released with the 4.3 Android version) and using the list navigation menu mode in the actionbar. The error occurs in the 2.3.3 version of android. I believe that's because in this version (and others versions), the whole actionbar code used is the compat-lib code.

When I click on the list menu (at the actionbar) my app crashes and I receive the following error at logcat:

07-30 18:17:59.296: E/AndroidRuntime(14701): FATAL EXCEPTION: main
07-30 18:17:59.296: E/AndroidRuntime(14701): java.lang.NullPointerException
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.support.v7.internal.widget.ListPopupWindow$DropDownListView.measureHeightOfChildrenCompat(ListPopupWindow.java:1317)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.support.v7.internal.widget.ListPopupWindow.buildDropDown(ListPopupWindow.java:1062)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.support.v7.internal.widget.ListPopupWindow.show(ListPopupWindow.java:514)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.support.v7.internal.widget.SpinnerICS$DropdownPopup.show(SpinnerICS.java:758)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.support.v7.internal.widget.SpinnerICS.performClick(SpinnerICS.java:443)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.view.View$PerformClick.run(View.java:9109)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.os.Handler.handleCallback(Handler.java:587)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.os.Handler.dispatchMessage(Handler.java:92)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.os.Looper.loop(Looper.java:130)
07-30 18:17:59.296: E/AndroidRuntime(14701):    at android.app.ActivityThread.main(ActivityThread.java:3683)
07-30 18:17:59.296: E/AndroidRunti