To fix this in a custom renderer I had to use reflection and it took awhile so here is the fix:
IntPtrtextViewClass = JNIEnv.FindClass(typeof(TextView)); IntPtr mCursorDrawableResProperty = JNIEnv.GetFieldID (textViewClass, "mCursorDrawableRes", "I"); JNIEnv.SetField (Control.Handle, mCursorDrawableResProperty, 0);
(Control is the EditText control in the custom renderer)
adapted from here http://forums.xamarin.com/discussion/comment/20938/#Comment_20938 and here http://stackoverflow.com/a/19796417/548975
This lets you turn the android:textCursorDrawable to null so you can see the cursor again. (In my case it was due to a white cursor on a white background in some versions of android.