Example: Something similar to GUICtrlSetStyle to add (or remove) extended style $WS_EX_COMPOSITED to File Explorer's (explorer.exe) treeview (SysTreeView32). Here is what I have so far: #include <Array.au3> #include <MsgBoxConstants.au3> #include <WinAPIDlg.au3> #include <WindowsConstants.au3> Example() Func Example() Local $aWinList = WinList("This PC - File Explorer") ;_ArrayDisplay($aWinList) ConsoleWrite($aWinList[1][1] & @CRLF) $hWnd = $aWinList[1][1] ;GUICtrlSetStyle($hWnd, -1, $WS_EX_COMPOSITED) ;MsgBox($MB_SYSTEMMODAL, "ID", "Dialog Control ID: " & _WinAPI_GetDlgCtrlID($hWnd)) ControlMove($hWnd, "", "[CLASS:SysTreeView32]", 0, 0, 150, 150) EndFunc ;==>Example The only purpose of the ControlMove function is to show me visually that I've got the right handle for explorer.exe and the right class. But that is far as I can get. Is there any way to set the extended style for the SysTreeView32 control of another process (explorer.exe)? Thank you for your time.

I use something like this in SMF internally, not tested on other processes. #include <GUIConstantsEx.au3> #include <WinAPISysWin.au3> #include <WindowsConstants.au3> Local $hGUI = GUICreate("Example", 400, 400) GUISetState(@SW_SHOW, $hGUI) Sleep(1000) __WinAPI_Set_Window_Style($hGUI, $WS_SIZEBOX, True, False) Sleep(5000) __WinAPI_Set_Window_Style($hGUI, $WS_SIZEBOX, False, False) Sleep(1000) __WinAPI_Set_Window_Style($hGUI, $WS_EX_TOOLWINDOW, True, True) Sleep(5000) __WinAPI_Set_Window_Style($hGUI, $WS_EX_TOOLWINDOW, False, True) While 1 Switch GUIGetMsg() Case $GUI_EVENT_CLOSE ExitLoop EndSwitch WEnd Func __WinAPI_Set_Window_Style($hWnd, $i_Style, $b_Add, $b_exStyle = False) If $b_exStyle = False Then Local $i_Style_Old = _WinAPI_GetWindowLong($hWnd, $GWL_STYLE) Else Local $i_Style_Old = _WinAPI_GetWindowLong($hWnd, $GWL_EXSTYLE) EndIf If $b_Add Then ; Style already applied If BitAND($i_Style_Old, $i_Style) Then Return Else ; Style not set If Not BitAND($i_Style_Old, $i_Style) Then Return EndIf If $b_exStyle = False Then If $b_Add Then _WinAPI_SetWindowLong($hWnd, $GWL_STYLE, BitOR($i_Style_Old, $i_Style)) Else _WinAPI_SetWindowLong($hWnd, $GWL_STYLE, BitXOR($i_Style_Old, $i_Style)) EndIf Else If $b_Add Then _WinAPI_SetWindowLong($hWnd, $GWL_EXSTYLE, BitOR($i_Style_Old, $i_Style)) Else _WinAPI_SetWindowLong($hWnd, $GWL_EXSTYLE, BitXOR($i_Style_Old, $i_Style)) EndIf EndIf _WinAPI_SetWindowPos($hWnd, $HWND_TOP, 0, 0, 0, 0, BitOR($SWP_FRAMECHANGED, $SWP_NOACTIVATE, $SWP_NOMOVE, $SWP_NOSIZE)) EndFunc ;==>__WinAPI_Set_Window_Style