Option Explicit

Dim Andocken As Boolean
Dim seite As Integer

Private Sub Form_Load()
  Form2.Show
  Me.Show
End Sub

Private Sub Command1_Click(Index As Integer)
  Select Case Index
    Case 1
      Command1(3).Enabled = True
      Andocken = True
      dock 0 ' links
    Case 2
      Command1(3).Enabled = True
      Andocken = True
      dock 1 ' rechts
    Case 3
      Command1(3).Enabled = True
      Andocken = False
    Case Else
      Unload Me
      End
  End Select
End Sub

Sub dock(x As Integer)
  Form2.Top = Me.Top
  seite = x
  If x = 1 Then
    Form2.Left = Me.Left + Me.Width + 5
  Else
    Form2.Left = Form1.Left - Form2.Width - 5
  End If
End Sub

Private Sub Timer1_Timer()
   If Andocken = True Then dock seite
End Sub