How can I tell when an MS Word dialog box is open?

I need to know when a user opens a dialog box in Word. I am working in a VB dll (add-in) with a timer that periodically queries a document for content, but if a dialog box is open I can't get a reference to the document. I get a "Component Request Pending" alert, "...because the component(Document1 - Microsoft Word) is busy. Choose 'Switch To'...". When I run this compiled, I do not get the alert, but the dialog box begins to flicker and the dialog actions begin to fail. Is there an application level or Office property that can tell me when a dialog box is open?

Thanks