BackgroundWorker Strangeness

Here is a very simplified example to demonstrate the issue.  This works just perfectly:

Dim MyBW As BackgroundWorker
Dim bwWorkers As New List(Of BackgroundWorker)

Private Sub btnDoSomething_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles btnDoSomething.Click

    MyBW = New BackgroundWorker
    Try
        With MyBW
            .WorkerReportsProgress = True
            .WorkerSupportsCancellation = True
        End With
        bwWorkers.Add(MyBW)
        MyBW.RunWorkerAsync()
    Catch ex As Exception
    
    End Try

End Sub

Private Sub MyBW_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles MyBW.DoWork

    Stop  'This is just for testing.

End Sub

But, If I have several different BackgroundWorkers, and want to reduce coding, I try this way:

Dim bwThis As BackgroundWorker
Dim bwThat As Backgroundworker
Dim bwWorkers As New List(Of BackgroundWorker)

Private Sub DoThis_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles DoThis.Click
    Dim isOK As Boolean = start_background_worker(bwThis)
End Sub

Private Sub DoThat_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles DoThat.Click
    Dim isOK As Boolean = start_background_worker(bwThat)
End Sub

Private Function start_background_worker(ByRef bw As BackgroundWorker) As Boolean
    Try
        bw = New BackgroundWorker
        With bw
            .WorkerReportsProgress = True
            .WorkerSupportsCancellation = True
        End With
        bwWorkers.Add(bw)
        bw.RunWorkerAsync()
        Return True
    Catch ex As Exception
        Return False
    End Try
End Function
Private Sub bwThis_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles bwThis.DoWork
    Stop  'This is just for testing.
End Sub
Private Sub bwThat_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles bwThat.DoWork
    Stop  'This is just for testing.
End Sub

Now I run into the problem.  When I click one or the other button to start the job, it doesn't start, and therefore doesn't hit the Stop statement in the DoWork method.  If I stop the Background worker, then start it a second time, it then works and hits the Stop statement.

One of the 2 BackgroundWorkers usually starts fine, and the other doesn't, and must be stopped/started again to work.  In another application, even the first and only BackgroundWorker has the issue.

Once it is restarted, everything works fine, and all of the BackgroundWorker events work properly.

Any idea what could be causing this?  Thanks...

Ron Mittelman