This example uses three list views. At start up all employees are added to the All Employees and Not Selected Employees list views. As employees are selected and deselected from the All Employees list they are added to and removed from the Selected Employees and Not Selected Employees list. 
To see how the example works, copy this code and paste it to a form component:
FUNCTION options(*DIRECT)
BEGIN_COM role(*EXTENDS #PRIM_FORM) HEIGHT(378) LEFT(345) TOP(196) WIDTH(473)
DEFINE_COM class(#PRIM_LTVW) name(#ALL_LIST) DISPLAYPOSITION(1) FULLROWSELECT(True) HEIGHT(313) LEFT(8) PARENT(#GPBX_ALL) TABPOSITION(1) TOP(16) WIDTH(129)
DEFINE_COM class(#PRIM_LTVW) name(#SEL_LIST) DISPLAYPOSITION(1) FULLROWSELECT(True) HEIGHT(313) LEFT(8) PARENT(#GPBX_SEL) TABPOSITION(1) TOP(16) WIDTH(129)
DEFINE_COM class(#PRIM_LTVW) name(#NOT_LIST) DISPLAYPOSITION(1) FULLROWSELECT(True) HEIGHT(313) LEFT(8) PARENT(#GPBX_NOT) TABPOSITION(1) TOP(16) WIDTH(129)
DEFINE_COM class(#PRIM_LVCL) name(#LVCL_1) DISPLAYPOSITION(1) PARENT(#ALL_LIST) SORTPOSITION(1) SOURCE(#EMPNO) WIDTH(54) WIDTHTYPE(Remainder)
DEFINE_COM class(#PRIM_LVCL) name(#LVCL_2) DISPLAYPOSITION(1) PARENT(#SEL_LIST) SORTPOSITION(1) SOURCE(#EMPNO) WIDTH(54) WIDTHTYPE(Remainder)
DEFINE_COM class(#PRIM_LVCL) name(#LVCL_3) DISPLAYPOSITION(1) PARENT(#NOT_LIST) SORTPOSITION(1) SOURCE(#EMPNO) WIDTH(54) WIDTHTYPE(Remainder)
DEFINE_COM class(#PRIM_GPBX) name(#GPBX_ALL) CAPTION('All Employees') DISPLAYPOSITION(3) HEIGHT(337) LEFT(8) PARENT(#COM_OWNER) TABPOSITION(3) TABSTOP(False) TOP(8) WIDTH(145)
DEFINE_COM class(#PRIM_GPBX) name(#GPBX_SEL) CAPTION('Selected Employees') DISPLAYPOSITION(2) HEIGHT(338) LEFT(156) PARENT(#COM_OWNER) TABPOSITION(2) TABSTOP(False) TOP(6) WIDTH(145)
DEFINE_COM class(#PRIM_GPBX) name(#GPBX_NOT) CAPTION('NOT Selected Employees') DISPLAYPOSITION(1) HEIGHT(339) LEFT(304) PARENT(#COM_OWNER) TABPOSITION(1) TABSTOP(False) TOP(5) WIDTH(145)
DEFINE field(#SEL_EMPNO) reffld(#EMPNO)
EVTROUTINE handling(#com_owner.Initialize)
- Add all employees to the all and not selected lists
SELECT fields(#ALL_LIST) from_file(PSLMST)
ADD_ENTRY to_list(#ALL_LIST)
ADD_ENTRY to_list(#NOT_LIST)
ENDSELECT
ENDROUTINE
EVTROUTINE handling(#ALL_List.ItemGotSelection) - Save employee number value
CHANGE field(#SEL_EMPNO) to(#EMPNO) - Add to Selected list
ADD_ENTRY to_list(#SEL_LIST) - Remove from the not selected list
SELECTLIST named(#NOT_LIST)
IF cond('#EMPNO = #SEL_EMPNO')
DLT_ENTRY from_list(#NOT_LIST)
LEAVE
ENDIF
ENDSELECT
ENDROUTINE
EVTROUTINE handling(#ALL_List.ItemLostSelection) - Save employee number value
CHANGE field(#SEL_EMPNO) to(#EMPNO) - Add to not Selected list
ADD_ENTRY to_list(#NOT_LIST) - Remove from the selected list
SELECTLIST named(#SEL_LIST)
IF cond('#EMPNO = #SEL_EMPNO')
DLT_ENTRY from_list(#SEL_LIST)
LEAVE
ENDIF
ENDSELECT
ENDROUTINE
END_COM