سلام
از کدهای زیر در رویداد MouseDown و MouseMove کنترل مربوطه در فرم اصلی استفاده کن !

Public xX As Single
Public yY As Single
Public winTop As Single
Public winLft As Single

Private Sub TitelBarCtl_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
winTop = Me.WindowTop
winLft = Me.WindowLeft
xX = X
yY = Y
End Sub

Private Sub TitelBarCtl_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
If X > xX Then
X = X - xX
winLft = winLft + X
Else
X = xX - X
winLft = winLft - X
End If
If Y > yY Then
Y = Y - yY
winTop = winTop + Y
Else
Y = yY - Y
winTop = winTop - Y
End If
Select Case Button
Case vbKeyLButton
Me.Move winLft, winTop
Forms("Form2").Move Me.WindowLeft, Me.WindowTop + Me.WindowHeight
End Select
End Sub

در اینجا نام کنترل مربوطه TitelBarCtl فرض شده