why does the bunifu textbox in the lost focus event cause errorprovider not being able to stop in VB.NET

Question

I'm Trying use the bunifu textbox in the lost focus event but cause errorprovider not being able to stop in VB.NET.

If I move from a Bunifu TextBox control to a standard TextBox control, it makes the textBox seem to move and I use the lostfocus event in the Bunifu TextBox so that the error provider can't stop if I run in the standard textbox then it runs normally

is there something wrong with my code?

Please Guide Me.

Thanks

Public Class Form3
    Dim TestAutoComplete As New AutoCompleteStringCollection
    Private Sub Form3_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.BunifuTextBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend
        Me.BunifuTextBox1.AutoCompleteSource = AutoCompleteSource.CustomSource
        Me.TextBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend
        Me.TextBox1.AutoCompleteSource = AutoCompleteSource.CustomSource
        TestAutoComplete.Add("Mahesh Chand")
        TestAutoComplete.Add("Mac Jocky")
        TestAutoComplete.Add("Millan Peter")
        BunifuTextBox1.AutoCompleteCustomSource = TestAutoComplete
    End Sub
    Private Sub BunifuTextBox1_TextChanged(sender As Object, e As EventArgs) Handles BunifuTextBox1.TextChanged
        If String.IsNullOrEmpty(BunifuTextBox1.Text) Then
            ErrorProvider1.SetError(BunifuTextBox1, "")
        Else
            If TestAutoComplete.Count > 0 Then
                ErrorProvider1.SetError(BunifuTextBox1, "")
            End If
        End If
    End Sub
    Private Sub BunifuTextBox1_LostFocus(sender As Object, e As EventArgs) Handles BunifuTextBox1.LostFocus
        TestAutoComplete.Add("Mahesh Chand")
        TestAutoComplete.Add("Mac Jocky")
        TestAutoComplete.Add("Millan Peter")
        BunifuTextBox1.AutoCompleteCustomSource = TestAutoComplete
        If BunifuTextBox1.Text = "C" And BunifuTextBox1.Text <> "" Then
            ErrorProvider1.SetError(BunifuTextBox1, "Name still doesn't match")
            MsgBox("Name still doesn't match")
            Application.DoEvents()
            BunifuTextBox1.SelectionStart = 0
            BunifuTextBox1.SelectionLength = BunifuTextBox1.Text.Length
            BunifuTextBox1.Select()
        End If
    End Sub
    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
        If String.IsNullOrEmpty(TextBox1.Text) Then
            ErrorProvider1.SetError(TextBox1, "")
        Else
            If TestAutoComplete.Count > 0 Then
                ErrorProvider1.SetError(TextBox1, "")
            End If
        End If
    End Sub
    Private Sub TextBox1_LostFocus(sender As Object, e As EventArgs) Handles TextBox1.LostFocus
        TestAutoComplete.Add("Mahesh Chand")
        TestAutoComplete.Add("Mac Jocky")
        TestAutoComplete.Add("Millan Peter")
        TextBox1.AutoCompleteCustomSource = TestAutoComplete
        If TextBox1.Text = "C" And TextBox1.Text <> "" Then
            ErrorProvider1.SetError(TextBox1, "Name still doesn't match")
            MsgBox("Name still doesn't match")
            Application.DoEvents()
            TextBox1.SelectionStart = 0
            TextBox1.SelectionLength = TextBox1.Text.Length
            TextBox1.Select()
        End If
    End Sub
End Class

RESULT WITH BUNIFU TEXTBOX

RESULT WITH STANDARD TEXTBOX