private void HandleDocumentVisibilityChange(uint docCookie, IVsWindowFrame frame, bool visible)
        {
            // Don't call this.docTable.GetDocumentInfo.  See notes in HandleDocumentLockChange.
            string moniker = this.docTable4.GetDocumentMoniker(docCookie);

            if (!string.IsNullOrEmpty(moniker))
            {
                DocumentItem document = visible ? new DocumentItem(DocumentItem.GetTextDocument(frame, this.adapterFactory)) : null;
                this.AddChangedDocument(moniker, document);
            }
        }
        private void TextBuffer_PostChanged(object sender, EventArgs e)
        {
            ITextDocument document = DocumentItem.GetTextDocument(sender as ITextBuffer);

            this.AddChangedDocument(document);
        }