title: add addtional summary row in smartgwt Grid
body: <p>Im trying to add a summary row which sum all values in each column. I have very large data and I do pagination in the grid. However, I heard gwt doing summaryGrid in client side which does not work in my case. I tried to setShowGridSummary to true but it works only for a small set of data, it shows blank if the data is large. So I want to change the plan to add additional summary grid and then get the query from backend and insert the summary data into that grid. So my question is can I add additional row into smartgwt grid? And how?</p>
  
  <p>Thanks,</p>