ProtectedViewWindow.Workbook Property (Excel)
Returns an object that represents the workbook that is open in the specified Protected View window. Read-only
Because a Protected View window is designed to protect the user from potentially malicious code, the operations you can perform by using a Workbook object returned by the Workbook method will be limited. Any operation that is not allowed will return an error.
A workbook displayed in a protected view window is not a member of the Workbooks collection. Instead, use the Workbook property of the ProtectedViewWindow object to access a workbook that is displayed in a protected view window.