Use the RClick event to add your context menu. The RClick event notifies your application when the user right clicks the control. Use the Click event to notify your application that the user clicks the control ( using the left mouse button ). Use the MouseDown or MouseUp event if you require the cursor position during the RClick event. Use the RClickSelect property to specify whether the user can select items by right clicking the mouse. Use the ItemFromPoint property to get the item from point. Use the ColumnFromPoint property to get the column from point. 

private void RClick(object sender)
{
}

Private Sub RClick(ByVal sender As System.Object) Handles RClick
End Sub

private void RClick(object sender, EventArgs e)
{
}

void OnRClick()
{
}

void __fastcall RClick(TObject *Sender)
{
}

procedure RClick(ASender: TObject; );
begin
end;

procedure RClick(sender: System.Object; e: System.EventArgs);
begin
end;

begin event RClick()
end event RClick

Private Sub RClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RClick
End Sub

Private Sub RClick()
End Sub

Private Sub RClick()
End Sub

LPARAMETERS nop

PROCEDURE OnRClick(oTree)
RETURN

<SCRIPT EVENT="RClick()" LANGUAGE="JScript">
</SCRIPT>

<SCRIPT LANGUAGE="VBScript">
Function RClick()
End Function
</SCRIPT>

Procedure OnComRClick 
	Forward Send OnComRClick 
End_Procedure

METHOD OCX_RClick() CLASS MainDialog
RETURN NIL

void onEvent_RClick()
{
}

function RClick as v ()
end function

function nativeObject_RClick()
return

The following VB sample use Exontrol's ExPopupMenu Component to display a context menu when user has clicked the right mouse button in the control's client area:

Private Sub Tree1_RClick()
    Dim i As Long
    i = PopupMenu1.ShowAtCursor
End Sub

If you need to add a context menu based on the item you can use the MouseUp event, like in the following VB sample:

Private Sub Tree1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
    If (Button = 2) Then
        ' Converts the container coordinates to client coordinates
        X = X / Screen.TwipsPerPixelX
        Y = Y / Screen.TwipsPerPixelY
        Dim h As HITEM
        Dim c As Long, hit as Long
        ' Gets the item from (X,Y)
        h = Tree1.ItemFromPoint(X, Y, c, hit)
        If Not (h = 0) Then
            Dim i As Long
            PopupMenu1.Items.Add Tree1.Items.CellCaption(h, c)
            i = PopupMenu1.ShowAtCursor
        End If
    End If
End Sub

The following VC sample displays the caption of the cell where the mouse is released:

#include "Items.h"

static CString V2S( VARIANT* pv, LPCTSTR szDefault = _T("") )
{
	if ( pv )
	{
		if ( pv->vt == VT_ERROR )
			return szDefault;

		COleVariant vt;
		vt.ChangeType( VT_BSTR, pv );
		return V_BSTR( &vt );
	}
	return szDefault;
}

void OnMouseUpTree1(short Button, short Shift, long X, long Y) 
{
	long c = 0, hit = 0, hItem = m_tree.GetItemFromPoint( X, Y, &c, &hit );
	if ( ( hItem != 0 ) || ( c != 0 ) )
	{
		CItems items = m_tree.GetItems();
		COleVariant vtItem( hItem ), vtColumn( c );
		CString strCaption = V2S( &items.GetCellCaption( vtItem, vtColumn ) ), strOutput;
		strOutput.Format( "Cell: '%s', Hit = %08X\n", strCaption, hit );
		OutputDebugString( strOutput );
	}
}

The following VB.NET sample displays the caption of the cell where the mouse is released:

Private Sub AxTree1_MouseUpEvent(ByVal sender As Object, ByVal e As AxEXTREELib._ITreeEvents_MouseUpEvent) Handles AxTree1.MouseUpEvent
    With AxTree1
        Dim i As Integer, c As Integer, hit As EXTREELib.HitTestInfoEnum
        i = .get_ItemFromPoint(e.x, e.y, c, hit)
        If (Not (i = 0) Or Not (c = 0)) Then
            Debug.WriteLine("Cell: " & .Items.CellCaption(i, c) & " Hit: " & hit.ToString())
        End If
    End With
End Sub

The following C# sample displays the caption of the cell where the mouse is released:

private void axTree1_MouseUpEvent(object sender, AxEXTREELib._ITreeEvents_MouseUpEvent e)
{
	int c = 0;
	EXTREELib.HitTestInfoEnum hit;
	int i = axTree1.get_ItemFromPoint( e.x, e.y, out c,out hit );
	if ( ( i != 0 ) || ( c != 0 ) )
	{
		string s = axTree1.Items.get_CellCaption( i,c ).ToString();
		s = "Cell: " + s + ", Hit: " + hit.ToString();
		System.Diagnostics.Debug.WriteLine( s );
	}
}

The following VFP sample displays the caption of the cell where the mouse is released:

*** ActiveX Control Event ***
LPARAMETERS button, shift, x, y

local c, hit
c = 0
hit = 0
with thisform.Tree1
	.Items.DefaultItem = .ItemFromPoint( x, y, @c, @hit )
	if ( .Items.DefaultItem <> 0 ) or ( c <> 0 )
		wait window nowait .Items.CellCaption( 0, c ) + " " + Str( hit )
	endif
endwith