Condition tab in display mode while creating sales order.

Hi Guys,

When I go to create a sales order the condition tab shows all the condition types in grey, irrrespective of its being manual or mandatory. I know it has nothing to do with V/06 or standard pricing transactions. So I changes the item categry.Again used the same order type, same customer , same material and same sales area. Once I change the item category to Zxxx, Condition tab becomes changeable. So I concluded that item category is the culprit. But the question is Which part of item category is influencing it ?

Please help.

Regards,