VBS: Select item in Windows Explorer last active window

I use the following code to select a file in a Windows Explorer window:

Set objShellAPP = CreateObject("Shell.Application")
objShellAPP.Open(WScript.Arguments(0))
WScript.Sleep(300)

On Error Resume Next        ' For new unsaved files.
With objShellAPP.Windows(objShellAPP.Windows.Count - 1).document
.SelectItem .Folder.Items.Item(WScript.Arguments(1)), 29
End With

Set objShellAPP = Nothing

objShellAPP.Open() opens the folder in the last active window;

objShellAPP.Windows.Count - 1 is not necessarily that window.

How can I get the last active window for the With objShellAPP.Windows(---).document line?

Thank you.

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See:

Open and Select a file in an existing Explorer window

VBS: Select one file in a folder