;Autor: MrMat

EnableExplicit

Define hWnd
Define header
Define a
Global oldproc.l
Global newheight.l

#LVM_GETHEADER = #LVM_FIRST + 31

Procedure.l WinProc(hWnd.l, Msg.l, wParam.l, lParam.l)
  Protected result.l
  Protected *hdlayout.HD_LAYOUT
  Protected *rect.RECT
  Protected *windowpos.WINDOWPOS
  
  result.l = 0
  If Msg = #HDM_LAYOUT
    result = CallWindowProc_(oldproc, hWnd, Msg, wParam, lParam)
    *hdlayout.HD_LAYOUT = lParam
    If *hdlayout\prc <> 0
      *rect.RECT = *hdlayout\prc
      *rect\top = newheight
    EndIf
    If *hdlayout\pwpos <> 0
      *windowpos.WINDOWPOS = *hdlayout\pwpos
      *windowpos\cy = newheight
    EndIf
  Else
    result = CallWindowProc_(oldproc, hWnd, Msg, wParam, lParam)
  EndIf
  ProcedureReturn result
EndProcedure

If OpenWindow(0,0,0,500,250,"Window",#PB_Window_SystemMenu|#PB_Window_ScreenCentered)
  ExplorerListGadget(1,10,10,480,230,"C:\",0)
  
  newheight = 50
  header = SendMessage_(GadgetID(1), #LVM_GETHEADER, 0, 0)
  oldproc = SetWindowLongPtr_(header, #GWL_WNDPROC, @WinProc())
  SetWindowPos_(header, 0, 0, 0, GadgetWidth(1), newheight, #SWP_NOZORDER | #SWP_NOMOVE)
  
Repeat : Until WaitWindowEvent() = #PB_Event_CloseWindow
EndIf