Sub probe()
Dim sc As New CorelDRAW.Color
' below one way which is working but only when Object Manager is visible.
ActivePage.Layers("Guides").OverrideColor = True
ActivePage.Layers("Guides").Color.CMYKAssign 100, 100, 0, 0
' below the second way which should be working but it's absolutely don't
'ActiveDocument.MasterPage.Layers("Guides").OverrideColor = True
'ActiveDocument.MasterPage.Layers("Guides").Color.CMYKAssign 0, 100, 100, 0
' test code
Set sc = ActiveDocument.MasterPage.Layers("Guides").Color
Debug.Print sc.CMYKCyan; sc.CMYKMagenta; sc.CMYKYellow; sc.CMYKBlack
End Sub