ActivePane Property
Returns a Pane object that represents the active pane for the specified window. Read-only.
Example
This example splits the active window and then activates the next pane after the active pane.
With ActiveDocument.ActiveWindow
.Split = True
.ActivePane.Next.Activate
MsgBox "Pane " & .ActivePane.Index & " is active"
End With
This example activates the first window and displays tabs in the active pane.
With Application.Windows(1)
.Activate
.ActivePane.View.ShowTabs = True
End With