Slider panel that hides components inside it

Question

What event(s) would I use to handle hiding a button/component that is inside this panel? This is a sliding panel that when the user hovers over, it expands and when the mouse exits, it collapses.

The problem is I don't know how to keep the components from showing until it is expanded.

 Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Panel1.Dock = DockStyle.Left
        Timer3.Enabled = True
    End Sub


    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        If Panel1.Width < 150 Then
            Panel1.Width = Panel1.Width + 100
        ElseIf Panel1.Width = 150 Then
            Timer1.Enabled = False
        End If
    End Sub

    Private Sub Timer2_Tick(sender As Object, e As EventArgs) Handles Timer2.Tick
        If Panel1.Width >= 100 Then
            Panel1.Width = Panel1.Width - 50
            If Panel1.Width < 100 And Panel1.Width > 25 Then
                Panel1.Width = Panel1.Width - 1
            End If

        ElseIf Panel1.Width = 25 Then
            Timer2.Enabled = False
        End If
    End Sub


    Private Sub Timer3_Tick(sender As Object, e As EventArgs) Handles Timer3.Tick
        If Panel1.ClientRectangle.Contains(Panel1.PointToClient(MousePosition)) Then
            If Not Timer1.Enabled AndAlso Panel1.Width < 150 Then
                Timer1.Enabled = True
                Timer2.Enabled = False
            End If
        Else
            If Not Timer2.Enabled AndAlso Panel1.Width > 25 Then
                Timer1.Enabled = False
                Timer2.Enabled = True
            End If
        End If
    End Sub


End Class

Answer 1

You should probably rename your timers to keep them straight, something like SlideOpenTimer and SlideCloseTimer, etc. Would make it easier to understand what the timers are for.

I re-worked your timer events to hide the ListBox when the closing timer starts and to show the ListBox when the panel reaches its full width:

Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
  If Panel1.Width < 100 Then
    Panel1.Width += 50
  ElseIf Panel1.Width < 150 Then
    Panel1.Width += 25
  ElseIf Panel1.Width >= 150 Then
    Timer1.Enabled = False
    ListBox1.Visible = True
  End If
End Sub

Private Sub Timer2_Tick(sender As Object, e As EventArgs) Handles Timer2.Tick
  If ListBox1.Visible Then
    ListBox1.Visible = False
  End If
  If Panel1.Width > 100 Then
    Panel1.Width -= 50
  ElseIf Panel1.Width > 25 Then
    Panel1.Width -= 25
  ElseIf Panel1.Width <= 25 Then
    Timer2.Enabled = False
  End If
End Sub