Unable to update grid container on combobox value change

Hi ,
I am using vaadin 7.7.7
In a grid i have a combobox as an edited item in one of the columns.
as

grid.addColumn("columnProperty").setEditorField(combobox);

I need to update a property/cell in same row based on the combobox selection change
My issue is , the selection change event triggers twice, once when the combobox in clicked and second when the selection value is changed. But the updated value in next cell gets reflected on UI only first time.
Below is the code written . Can you help me with this?

Combobox.addValueChangeListener(new ValueChangeListener()
{
@Override
public void valueChange(ValueChangeEvent event) {
// below line works only first time when the combobox is clicked,but i want it when the item in the combobox is //changed
gridContainer.getContainerProperty(editedRow, "editedColumProperty").setValue("ValueTobeUpdated");
}
});

Generally if you do setEditorField(…), you should not need to use value change listener at all.

but then I need to update other fields in grid container row based on the combobox selection change before commit. Both the combobox and other element to update are in a single row.

For example ,grid has 2 columns ,parameter(combobox) and its unit. so when i change the parameter combobox ,i need to update the adjacent cell based on the selection before commit. Hope i am not confusing.