CountVisibleChoices
return fCompletionStyle->GetChoiceView()->CountVisibleChoices();
int32 CountVisibleChoices() const;
virtual int32 CountVisibleChoices() const = 0;
virtual int32 CountVisibleChoices() const;
int32 index = SelectedChoiceIndex() - CountVisibleChoices();
int32 index = SelectedChoiceIndex() + CountVisibleChoices();