Have you ever checked placing a report with object prompt in report service document? if so, then the object prompt won’t appear in document.
- Place all the attributes (which present in object prompt) in to the report
- Add as a data set into report service document.
- Drag and drop the report(grid) into the document.
- Save and close the document.
- Open the report, remove all the attributes and place the object prompt into the same place (column or row) where attributes are placed.
- Save and close the report.
- Now, execute the document.
No wonder, it will ask you to select the attributes from the list.