[IButton,???,"Press to select previous mesh of MultiMesh brush (IMM, VDM etc)",
    [VarSet, MMSelPath, "Brush:Modifiers:MultiMeshSelect"]

    [If, [IsDisabled,MMSelPath]=1,
        [Exit]
    ]

    [VarSet, CurMeshIdx, [IGet,MMSelPath]]

    [If, CurMeshIdx>0
    ,
        [ISet,MMSelPath, CurMeshIdx-1]
    ,

        [ISet,MMSelPath, [IGetMax,MMSelPath]]
    ]

    [IUpdate,1,1]
]