There are probably better ways to do it, but here's one that works: #include <GUIConstantsEx.au3> #include <WindowsConstants.au3> #include <ProgressConstants.au3> #include <WinAPI.au3> #include <GuiTreeView.au3> #include <Array.au3> Global $form_si, $form_i, $form_L, $form_P $FormMain = GUICreate("Form1", 441, 360, 192, 124,BitOR( $WS_SYSMENU, $WS_CLIPCHILDREN, $WS_CLIPSIBLINGS, $WS_BORDER))