Hi bouhmid86,

To achieve this, you could try to implement an approach similar to the following:

XAML:
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="auto"/>
        </Grid.RowDefinitions>
       
        <igMap:XamMap x:Name="map1" Grid.Row="0">
            <igMap:XamMap.Layers>
                <igMap:MapLayer x:Name="statesLayer" Imported="statesLayer_Imported">
                    <igMap:MapLayer.Reader>
                        <igMap:ShapeFileReader Uri="Shapefiles/usa/usa_st" DataMapping="Name=STATE_NAME; Value=POP1997; Caption=STATE_ABBR"/>
                    </igMap:MapLayer.Reader>
                </igMap:MapLayer>
            </igMap:XamMap.Layers>
        </igMap:XamMap>
       
        <Button x:Name="btnRemoveTexasToolTip" Content="Remove TX Tooltip" Click="btnRemoveTexasToolTip_Click" Width="300" Height="100" Grid.Row="1"/>
    </Grid>

CB:
        private void statesLayer_Imported(object sender, Infragistics.Controls.Maps.MapLayerImportEventArgs e)
        {
            if (e.Action == Infragistics.Controls.Maps.MapLayerImportAction.End)
            {
                Point originNebraska = map1.MapProjection.ProjectToMap(new Point(-101.60, 42.90));
                Point originTexas = map1.MapProjection.ProjectToMap(new Point(-96.3, 29.9));

                SymbolElement elementNebraska = new SymbolElement() { SymbolOrigin = originNebraska, Caption = "Nebraska", SymbolType = MapSymbolType.Diamond, SymbolSize = 20, ToolTip = "NebraskaSymbolTooltip" };
                SymbolElement elementTexas = new SymbolElement() { SymbolOrigin = originTexas, Caption = "Texas", SymbolType = MapSymbolType.Hourglass, SymbolSize = 20, ToolTip = "TexasSymbolTooltip" };

                map1.Layers[0].Elements.Add(elementNebraska);
                map1.Layers[0].Elements.Add(elementTexas);
            }
        }

        private void btnRemoveTexasToolTip_Click(object sender, RoutedEventArgs e)
        {
            foreach (MapElement el in map1.Layers[0].Elements)
            {
                if (el.Caption == "Texas")
                {
                    el.ToolTip = null;
                }
            }
        }

Best Regards,
Milana Zhileva