Dropdown list fails to set a variable when its repopulated

[clarcombefmsb]

I have two dropdowns - Service and Department.  Each service has several departments

The two dropdowns are created from DISTINCT CONCAT of SERVICE_DESC and DEPT_DESC and populate vServiceList and vDeptList respectively

If I choose a new Service, the vServiceList variable is set and  the Department dropdown is also repopulated. However, the first value shown in the Department dropdown doesn't set the variable vDeptList and so fails to update the set expression.

The Set expression is

Sum(
    {$
    	<
	       [SERVICE_DESC_$(vLang)]={'$(vServiceList)'}
          ,[DEPT_DESC_$(vLang)]={'$(vDeptList)'}
     
		>
    }
    (BALANCE_REACTIVATED / IN_MD /7 ) + (BALANCE_TO_HANDLE / IN_MD/7 )
   )
/
Count(
      {$
         <
	        [SERVICE_DESC_$(vLang)]={'$(vServiceList)'}
           ,[DEPT_DESC_$(vLang)]={'$(vDeptList)'}
         >
       }
       	distinct TDB_DT
     )

Question

When the SERVICE dropdown is selected and vServiceList is set, how can I ensure that vDeptList gets set at the same time from the first entry in the DEPARTMENT dropdown, so that the set expression works correctly ?

The SMAB service is chosen and the department is updated and shown but the graph is not refreshedI have to click on the department, then choose another department to get the display to update

[kaushiknsolanki]

Need to check how you are setting the variables.

Can you share sample qvf file.

[clarcombefmsb]

Here is the file. Thanks