private Shape RetrieveCategoryNameBox(PowerPointSlide slide)
{
var nameBoxCandidate = slide.GetShapesWithTypeAndRule(MsoShapeType.msoTextBox, new Regex(".+"));
if (nameBoxCandidate.Count == 0)
{
return null;
}
var categoryNamePattern = new Regex(CategoryNameBoxSearchPattern);
// return the first match name box
return nameBoxCandidate.FirstOrDefault(x => categoryNamePattern.IsMatch(x.TextFrame.TextRange.Text));
}