The ActiveSelection property returns the active selection in the active document.
Examples:
The following VBA example colors the selected shapes green, if the shape selected is an ellipse.
Sub SelectionActive()
Dim s As Shape
For Each s In ActiveSelection.Shapes
If s.Type = cdrEllipseShape Then
s.Fill.UniformColor.CMYKAssign 100, 0, 100, 0
End If
Next s
End Sub