Word interop- ParentContentControl is null for content control contained within a simple text box

Question

Hi,

I am using word interop to edit docx files. In word doument I can have multiple nested content controls, in some cases I have a content control 'A' containing a text box (simple text box inserted from Insert-Text box-simple text box) the text box contains in turn a content control 'B'. When entering the nested content control 'B', I want to identify the parent content control that is 'A' here. I am using the ContentControl.ParentContentControl property to get the top parent content control , the problem that for the content controls contained within text box ParentContentControl property is null.

How can I get the top parent content control for the child content controls caintained into text box?

Regards.