DucViet321, If you create subframes then you need to create them using the handle of the frame in which it will fit - you were using the main GUI and that will not work as it is already subdivided. Checking in the UDF you can only set the separator width to between 3 and 9 pixels - outside that range will default to 5 pixels. I seem to remember that it was difficult to see the separator if you made it any smaller than 3 pixels wide. By all means change the relevant lines in the UDF of you want to experiment, but I will not offer support if you do.
; Set separator size
Local $iSeparatorSize = 5
Switch $iSepSize
Case 3 To 9 ; Just change these values <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
$iSeparatorSize = $iSepSize
EndSwitch
Where do you want your ListView created? At present it will appear in the right-hand frame of the subframe as that is the last GUI created. In this script I have used the _GUIFrame_Switch function to set the active GUI to the left-hand frame of the main frame - is that what you intended?
#include <GUIFrame.au3>
#include <GUIListView.au3>
#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>
$hGUI = GUICreate("test", 500, 500, -1, -1, BitOR($WS_MINIMIZEBOX, $WS_MAXIMIZEBOX, $WS_SIZEBOX))
GUISetState()
; Create a 1st level frame
$iFrame_A = _GUIFrame_Create($hGUI, 0, 0, 5)
_GUIFrame_SetMin($iFrame_A, 50, 100)
; Create a 2nd level frame
$iFrame_B = _GUIFrame_Create(_GUIFrame_GetHandle($iFrame_A, 2), 0, 0, 5) ; You need to handle of the frame, not the GUI <<<<<<<<<<<<<<<<<<<
_GUIFrame_SetMin($iFrame_B, 100, 100)
_GUIFrame_Switch($iFrame_A, 1) ; Switch to the frame in which you want to create the ListView <<<<<<<<<<<<<<<<<<<<<<<<
$cListView = GUICtrlCreateListView(" | ", 5, 5, 240, 460)
GUICtrlSendMsg(-1, $LVM_SETCOLUMNWIDTH, 0, 50)
GUICtrlSendMsg(-1, $LVM_SETCOLUMNWIDTH, 1, 50) ; Set the width of both columns <<<<<<<<<<<<<<<
; Set resizing flag for all created frames
_GUIFrame_ResizeSet(0)
; Register the $WM_SIZE handler to permit resizing
_GUIFrame_ResizeReg()
GUICtrlCreateListViewItem("item|123", $cListView)
While 1
Switch GUIGetMsg()
Case $GUI_EVENT_CLOSE
Exit
EndSwitch
WEnd
All clear now? M23