Use the VisuapAppearance property to access the tooltip's Appearance collection. Use the Appearance property to specify the tooltip's border. Use the BackColor property to specify the tooltip's background color. Use the ForeColor property to specify the tooltip's foreground color. 

The following VB sample changes the border of the tooltip, using an EBN file:

Private Sub Form_Load()
    Set t = New EXTOOLTIPLib.ToolTip
    With t
        .VisualAppearance.Add &H12, "c:\temp\winword.ebn"
        t.Appearance = &H12000000
        t.BackColor = RGB(255, 255, 255)
    End With
End Sub

The following VB.NET sample changes the border of the tooltip, using an EBN file:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    t = New EXTOOLTIPLib.ToolTip
    t.VisualAppearance.Add(&H12, "c:\temp\winword.ebn")
    t.Appearance = &H12000000
    t.BackColor = ToUInt32(Color.White)
End Sub

where the ToUInt32 function is defined like follows:

Shared Function ToUInt32(ByVal c As Color) As UInt32
    Dim i As Long
    i = c.R
    i = i + 256 * c.G
    i = i + 256 * 256 * c.B
    ToUInt32 = Convert.ToUInt32(i)
End Function

The following C# sample changes the border of the tooltip, using an EBN file:

private void Form1_Load(object sender, EventArgs e)
{
    t = new EXTOOLTIPLib.ToolTip();
    t.VisualAppearance.Add(0x12, "c:\\temp\\winword.ebn");
    t.Appearance = (EXTOOLTIPLib.AppearanceEnum)0x12000000;
    t.BackColor = ToUInt32(Color.White);
}

where the ToUInt32 function is defined like follows:

private UInt32 ToUInt32(Color c)
{
	long i;
	i = c.R;
	i = i + 256 * c.G;
	i = i + 256 * 256 * c.B;
	return Convert.ToUInt32(i);
}

The following C++ sample changes the border of the tooltip, using an EBN file:

void initToolTip()
{
	CoInitialize( NULL );
	if ( SUCCEEDED( CoCreateInstance( __uuidof(EXTOOLTIPLib::ToolTip), NULL, CLSCTX_ALL, __uuidof(EXTOOLTIPLib::IToolTip), (LPVOID*)&m_spToolTip ) ) )
	{
		m_spToolTip->VisualAppearance->Add( 0x12, COleVariant( "c:\\temp\\winword.ebn" ) );
		m_spToolTip->Appearance = (EXTOOLTIPLib::AppearanceEnum)0x12000000;
		m_spToolTip->BackColor = RGB(255,255,255);
	}
}

The following VFP sample changes the border of the tooltip, using an EBN file:

public t as Object
t = CreateObject("Exontrol.ToolTip")

with t
	.VisualAppearance.Add(0x12,"c:\temp\winword.ebn")
	.Appearance = 0x12000000
    .BackColor = RGB(255,255,255)
endwith