This example shows you how to add an icon to the system tray, like many other utilities (ie a Virus Scanner).

First, add two Image Controls to your form, named imgOne, and imgTwo, and set their Picture properties to two different icons sized 16x16 (You can find some icons at %VBInstallPathCommonGraphics). Next, add a PictureBox called picHook. Finally, you need to add a menu item called mnuPopup, with two sub menu items called mnuPopupAbout and mnuPopupExit. Then, add the code below to the form.

Private Type NOTIFYICONDATA
    cbSize As Long
    hWnd As Long
    uId As Long
    uFlags As Long
    ucallbackMessage As Long
    hIcon As Long
    szTip As String * 64
End Type

Private Const NIM_ADD = &H0
Private Const NIM_MODIFY = &H1
Private Const NIM_DELETE = &H2
Private Const WM_MOUSEMOVE = &H200
Private Const NIF_MESSAGE = &H1
Private Const NIF_ICON = &H2
Private Const NIF_TIP = &H4

Private Const WM_LBUTTONDBLCLK = &H203
Private Const WM_LBUTTONDOWN = &H201
Private Const WM_LBUTTONUP = &H202
Private Const WM_RBUTTONDBLCLK = &H206
Private Const WM_RBUTTONDOWN = &H204
Private Const WM_RBUTTONUP = &H205

Private Declare Function Shell_NotifyIcon Lib "shell32" Alias "Shell_NotifyIconA" (ByVal dwMessage As Long, pnid As NOTIFYICONDATA) As Boolean
Dim T As NOTIFYICONDATA

Private Sub Form_Load()
   
    'Setup initial Tray Icon
    T.cbSize = Len(T)
    T.hWnd = pichook.hWnd
    T.uId = 1&
    T.uFlags = NIF_ICON Or NIF_TIP Or NIF_MESSAGE
    T.ucallbackMessage = WM_MOUSEMOVE
    T.hIcon = imgOne.Picture
    T.szTip = "Recent" & Chr$(0)
    Shell_NotifyIcon NIM_ADD, T
   
    'Hide this form
    Me.Hide
End Sub


Private Sub Form_Unload(Cancel As Integer)
    'Unload this form. Important: always end with "unload me".
    T.cbSize = Len(T)
    T.hWnd = pichook.hWnd
    T.uId = 1&
    Shell_NotifyIcon NIM_DELETE, T
    End
End Sub

Private Sub mnuPopupAbout_Click()
    MsgBox "Popup Example", , "About..."
End Sub

Private Sub mnuPopUpExit_Click()
    Unload Me
End Sub

Private Sub pichook_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
 Static State As Boolean
 Static Popped As Boolean
 Static Msg As Long
 
    Msg = X / Screen.TwipsPerPixelX
    If Popped = False Then
        'As we don't want any popups during the processing,
        'turn off the MouseMove event by setting popped=true
        Popped = True
       
        'Se the general section on how to interpret Msg
        Select Case Msg
            Case WM_LBUTTONDBLCLK
                mnuPopupAbout_Click
               
            Case WM_LBUTTONDOWN
                'In this case we have a twostate button, On or Off.
                State = Not State
                If State Then
                    'Set picture
                    T.hIcon = imgTwo.Picture
                    'Set tooltip
                    T.szTip = "Off" + Chr$(0)
                Else
                    T.hIcon = imgOne.Picture
                    T.szTip = "On" + Chr$(0)
                End If
                Shell_NotifyIcon NIM_MODIFY, T
               
            Case WM_LBUTTONUP
           
            Case WM_RBUTTONDBLCLK
           
            Case WM_RBUTTONDOWN
           
            Case WM_RBUTTONUP
                PopupMenu mnuPopup, 2, , , mnuPopupAbout
               
        End Select
        'OK to popup again
        Popped = False
    End If
End Sub