Application object: Returns a Windows collection that represents all the windows in all the workbooks. Read-only.
Workbook object: Returns a Windows collection that represents all the windows in the specified workbook. Read-only.
For information about returning a single member of a collection, see Returning an Object from a Collection.
Remarks
Using this property without an object qualifier is equivalent to using Application.Windows.
This property returns a collection of both visible and hidden windows.