table control with checkbox in module pool

Hi all,

I have a slight issue in my table control with checkbox. My requirement is that in the basic list the user can checkbox a few sales orders and in the selected sales orders will be displayed in the secondary list. However, the problem is that in spite of the sales orders that are selected, the secondary list is displaying all the sales orders from the basic list and not the ones that are selected. So, it seems that the internal table in the basic list is not getting modified accordingly. I have attached the screenshots for your reference. Please help me identify the error.

These are the variables I declared:

For the basic list:

Screenshot for the layout. Here I have inserted a function code for the checkbox as CBOX.

Code for user command:

The basic list is fine as shown.  Here 4970 and 4972 are selected:

However, the secondary list is displaying all the values from the basic list, not the selected values. Why?