In paging grid if i select a single row then selection is getting saved as [,1]

Can you check to make sure that the CDT is not initialized elsewhere with a blank value? This is the first one you should check. In general, for situations like this, the simplest work-around is to check if the first value is null and if so, do an LDROP. But I would figure out the source of the issue before doing a fix for a work-around

Any idea what might cause the null value to be saved? It's happening for me on a start form, with the pv set to be a parameter with values 'from form'. If I select 2 rows in the paging grid, the resulting pv is saved as [,1,2]