How do I eliminate Windows Form doppelganger?

Question

I have a single vb.net Form with a few buttons, a progressBar and a textBox that get updated regularly. After clicking the button to start some intensive processing, if I move the window, there's an exact duplicate underneath. The duplicate is locked, but it shows the same progress control operating exactly the same as the original. The main window shows "not responding".

Using .NET 5.0, and visual studio 2019.

I can't seem to find a description of the problem in all my searches.

Can anyone help? I can't believe I'm the first to experience such.

Thanks

Answer 1

This version doesn't give the duplicate window. As soon as you attempt to move the window, it becomes non-responsive and the controls (ProgressBar and TextBox) stop updating. I will provide a version that does ghost shortly. I believe there's an additional "Update" that causes the duplicate.

Option Compare Text
Public Class GenBootlegTxts
Public foldersProcessedCount As Int64
Private Sub GenBootlegTxts_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ProgressBar.Minimum = 0
ProgressBar.Maximum = 1000
ProgressBar.Step = 25
ProgressMinimum.Text = "0"
ProgressMinimum.Update()
Dim tNum As Int64 = 1000
ProgressMaximum.Text = tNum.ToString("#,#")
ProgressMaximum.Update()
End Sub

Sub GenTxtsButton_Click(sender As Object, e As EventArgs) Handles GenTxtsButton.Click
    NextLevel()
End Sub
Private Sub NextLevel()
    foldersProcessedCount += 1
    Do While True
        foldersProcessedCount += 1
        If foldersProcessedCount Mod 25 = 0 Then
            UpdateProcessingProgress(foldersProcessedCount)
        End If
    Loop
End Sub

Private Sub UpdateProcessingProgress(count As Int64)
    If count >= ProgressBar.Maximum * 0.85 Then
        ProgressBar.Maximum += ProgressBar.Maximum
        ProgressMaximum.Text = ProgressBar.Maximum.ToString("#,#")
        ProgressMaximum.Update()
    End If
    ProgressBar.PerformStep()
    ProgressTextBox.Text = "# processed: " & foldersProcessedCount
    ProgressTextBox.Update()
End Sub

Answer 2

If I add a ProgressBar.Upgrade between 22 and 23 above, it allows me to eventually move the window, but the controls stop updating. If I add a MsgBox that pops up every 150K iterations or so, it's clear that the software is still running, and when the MsgBox pops up, the controls start working again until I try and move it.

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