Missing Toolbar buttons missing after creating a tab grid by extending to an existing customization

I have an existing custom customisation I have to work with.  

Below is the Dac for the grid I want to add and the graph extension to be used

  [Serializable]

    [PXCacheName("TestTable")]

    [PXPrimaryGraph(typeof(TSSTStudentEntryExt))]

    public class TestTable : IBqlTable

    {

        #region LineNbr

        [PXDBIdentity(IsKey = true)]

        [PXUIField(DisplayName = "Line Nbr")]

        public virtual int? LineNbr { get; set; }

        public abstract class lineNbr : PX.Data.BQL.BqlInt.Field<lineNbr> { }

        #endregion

        #region StudentType

        [PXDBString(2, IsFixed = true, IsKey = true)]

        [PXDefault(typeof(TSSTStudent.StudentType))]

        [PXUIField(DisplayName = "Student Type", Visible = false, Enabled = false)]

        public virtual string StudentType { get; set; }

        public abstract class StudentType : PX.Data.BQL.BqlString.Field<StudentType> { }

        #endregion

        #region StudentNbr

        [PXDBString(15, IsKey = true, IsUnicode = true, InputMask = "")]

        [PXDBDefault(typeof(TSSTStudent.StudentNbr), DefaultForUpdate = false)]

        [PXParent(typeof(SelectFrom<TSSTStudent>.Where<TSSTStudent.StudentNbr.IsEqual<TestTable.StudentNbr.FromCurrent>.

            And<TSSTStudent.StudentType.IsEqual<TestTable.StudentType.FromCurrent>>>))]

        public virtual string StudentNbr { get; set; }

        public abstract class StudentNbr : PX.Data.BQL.BqlString.Field<StudentNbr> { }

        #endregion

}

  public class TSSTStudentEntryExt : PXGraphExtension<TSSTStudentEntry>

    {

    public PXSelect<TestTable,

        Where<TestTable.StudentType, Equal<Current<TSSTStudent.StudentType>>,

            And<Where<TestTable.StudentNbr, Equal<Current<TSSTStudent.StudentNbr>>>>>> TestDetail;

    }

TSSTStudent DAC has StudentType and StudentNbr as keys in its DAC.

Problem :  I am able to get the grid to show with the column but the standard toolbar for add and remove does not show.