If you offer functions on your tab page, which change the work item data, you should inform the SAP main screen of such changes.

This ensures that the main screen and the other tab pages update the data displayed.

The macro used for this purpose is:

SWL_WIDISP_SET_DIRTY

The macro could be implemented as follows:

[...]
case okay.
  when ´XXX1´.
    perform change_workitems_text.
    swl_widisp_set_dirty.
[...]