title: Count of related column doesn't work in Power Pivot
body: <p>I have few tables in my data source in Power Pivot:
  One is a "Calendar" table from Azure Marketplace (<a href="http://datamarket.azure.com/dataset/boyanpenev/datestream" rel="nofollow">http://datamarket.azure.com/dataset/boyanpenev/datestream</a>) that I'm using for user friendly date representation. Clients table that has basic information about clients (ClientId, Client Name, Recent Address). Each clients may have multiple Accounts (AccountId, Account Name, ClientId). And I have AccountActivity table (AccountId, Date, Income). I've setup relations between tables accordingly.</p>
  
  <p>I need to build a resulting table that is based off AccountActivity and will have Date(Month, Year), Sum of Incomes, # of accounts and # of clients. I was able to get everything except # of clients. Once I'm adding # of clients into the table it starts to complain that there is no reference and instead of showing proper # of clients it is showing total # of clients that does not have any relation to the accounts. Is there any way of making it work or I will have to add into AccountActivity ClientId column?</p>