#include <GUIConstantsEx.au3>
#include <GUIListBox.au3>
$hGui = GUICreate('Test', 400, 200)
$nList1 = GUICtrlCreateList('', 10, 10, 185, 180)
$nList2 = GUICtrlCreateList('', 195, 10, 185, 180)
GUISetState()
For $i = 1 To 10
GUICtrlSetData($nList1, $i & ' string')
GUICtrlSetData($nList2, $i & $i & ' string')
Next
While 1
$nMsg = GUIGetMsg()
Switch $nMsg
Case $GUI_EVENT_CLOSE
Exit
Case $nList1
_GUICtrlListBox_SetCurSel(GUICtrlGetHandle($nList2), -1)
MsgBox(0, '', GUICtrlRead($nList1))
Case $nList2
_GUICtrlListBox_SetCurSel(GUICtrlGetHandle($nList1), -1)
MsgBox(0, '', GUICtrlRead($nList2))
EndSwitch
WEnd