Hello,

 I am not sure what is going on with the application.  I set up a similar scenario to test this and was not able to reproduce the problem.  I have a button that calls BackgroundWorker1.RunWorkerAsync(). 

Then in DoWork, I fill a DataTable with some infomration. 

Private Sub BackgroundWorker1_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
        dt = TestData()
    End Sub 

Then in RunWorkerComplete, I set the DataSource of the grid to that DataTable. 

 Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        UltraGrid1.DataSource = dt
    End Sub

Then the InitializeLayout is fired and I hide two columns using the hidden property.

Private Sub UltraGrid1_InitializeLayout(ByVal sender As System.Object, ByVal e As Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs) Handles UltraGrid1.InitializeLayout
        e.Layout.Bands(0).Columns(0).Hidden = True
        e.Layout.Bands(0).Columns(1).Hidden = True
    End Sub

 When the grid is rendered, the two columns are hidden.  Try the sample code below at your end to see if it works or not.  If it does not, please contact Developer Support and provide them the information and they should be able to diagnose your problem.  I am not sure what version of the controls that you are using, so I can't test and know for sure whether this is an issue with the application or the infragistics control itself.  Hope this helps

Here is the complete code.  All I have on the form is the Ultragrid, a button, and a backgroundworker.

Public Class Form1
    Dim dt As DataTable
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        BackgroundWorker1.RunWorkerAsync()
    End Sub

    Private Sub UltraGrid1_InitializeLayout(ByVal sender As System.Object, ByVal e As Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs) Handles UltraGrid1.InitializeLayout
        e.Layout.Bands(0).Columns(0).Hidden = True
        e.Layout.Bands(0).Columns(1).Hidden = True
    End Sub

    Private Sub BackgroundWorker1_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
        dt = TestData()
    End Sub

    Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        UltraGrid1.DataSource = dt
    End Sub
    Function TestData()
        Dim NumberOfRecords As Integer = 10
        Dim dtData As New DataTable

        dtData.Columns.Add("Column_1", GetType(Object))

        dtData.Columns.Add("Column_2", GetType(String))

        dtData.Columns.Add("Column_3", GetType(Integer))
        Dim i As Integer
        For i = 1 To NumberOfRecords
            Dim dr As DataRow
            dr = dtData.NewRow()
            dr(0) = "Col 1 Row " + i.ToString()
            dr(1) = "Some Text " + i.ToString()
            dr(2) = i
            dtData.Rows.Add(dr)
        Next

        Return dtData

    End Function

End Class