Private Declare Function SetCapture Lib "user32.dll" _
  (ByVal hwnd As Long) As Long
 
Private Declare Function ReleaseCapture Lib "user32.dll" _
  () As Long
 
Private Sub Command1_MouseMove(Button As Integer, Shift As Integer, X As _
  Single, Y As Single)
 With Command1
    If X >= 0 And Y >= 0 And X <= .Width And Y <= .Height Then
      SetCapture .hwnd
      .BackColor = vbRed
    Else
      ReleaseCapture
      .BackColor = vbBlue
    End If
 End With
End Sub