while creating gl master record there will be one field 
called open item management where we need to tick the 
indicator so that at the time of posting any invoice 
relating to debtors or creditors automatically the invoice 
whatever we have posted will be shown as an open item which 
means that has to be cleared or payment has to be done. 
when we want to check the customer or vendor balances it 
will be shown with a red mark which indicsates that it is 
an open item management