Ok, here is a complete program.  First file is the form, second is the
UserControl in question.

Run it and click button1 repeatedly. Memory will keep growing and growing
with every click (500K at a time or so).

Stop it, and run it again. This time click button2 repeatedly.  Memory will
grow at first, but remain steady - growing maybe 4-20K at a time - so barely
noticeable.

Thanks for your interest...

Form:

Public Class Form1
Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
Public Sub New()
MyBase.New()
'This call is required by the Windows Form Designer.
InitializeComponent()
'Add any initialization after the InitializeComponent() call
End Sub
'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
Friend WithEvents Button1 As System.Windows.Forms.Button
Friend WithEvents Button2 As System.Windows.Forms.Button
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
Me.Button1 = New System.Windows.Forms.Button
Me.Button2 = New System.Windows.Forms.Button
Me.SuspendLayout()
'
'Button1
'
Me.Button1.Location = New System.Drawing.Point(24, 24)
Me.Button1.Name = "Button1"
Me.Button1.TabIndex = 0
Me.Button1.Text = "Button1"
'
'Button2
'
Me.Button2.Location = New System.Drawing.Point(24, 64)
Me.Button2.Name = "Button2"
Me.Button2.TabIndex = 1
Me.Button2.Text = "Button2"
'
'Form1
'
Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
Me.ClientSize = New System.Drawing.Size(552, 598)
Me.Controls.Add(Me.Button2)
Me.Controls.Add(Me.Button1)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
End Sub
#End Region
Dim curControl As UserControl
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
If Not IsNothing(curControl) Then
curControl.Dispose()
End If
curControl = New UserControl1
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button2.Click
If Not IsNothing(curControl) Then
Controls.Remove(curControl)
End If
curControl = New UserControl1
curControl.Location = New Point(50, 50)
Controls.Add(curControl)
End Sub
End Class

UserControl:

Public Class UserControl1
Inherits System.Windows.Forms.UserControl
#Region " Windows Form Designer generated code "
Public Sub New()
MyBase.New()
'This call is required by the Windows Form Designer.
InitializeComponent()
'Add any initialization after the InitializeComponent() call
init()
End Sub
'UserControl1 overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
'
'UserControl1
'
Me.Name = "UserControl1"
Me.Size = New System.Drawing.Size(392, 424)
End Sub
#End Region
Dim myData As New ArrayList
Public Sub init()
For i As Integer = 1 To 1000
Dim t As TextBox = New TextBox
t.Location = New Point(0, i * 40)
t.Text = i & "test"
Me.Controls.Add(t)
myData.Add(i & "test")
Next
End Sub
End Class