You should add this info to documentation

[Keoz]

When using the map control and having to add items to an information layer dynamically from code is important that you need to use a  ObservableCollection<FrameworkElement> instead of a List<FrameworkElement>, the list will add the elements to the map as you add it in code but will add frameworkelements in the location you specify and when you move the map the element will move to and not stay at the location specified, this does not happen with ObservableCollection

[Andrey]

Hi Jorge,

Similar to most of the items controls the InformationLayer can use any IEnumerable as items source. The List<FrameworkElement> can be used as well as ObservableCollection<FrameworkElement>. For example, the code below adds few geographically positioned rectangles to the list of the framework elements and then set this list as source for the information layer.

List<FrameworkElement> source = new List<FrameworkElement>();

for(int i = 0; i < 10; i++)
{
    Rectangle rect = new Rectangle()
    {
        Width = 50,
        Height = 50,
        Fill = new SolidColorBrush(Colors.Red)
    };
    MapLayer.SetLocation(rect, new Location(i * 2, 0));
    source.Add(rect);
}

this.informationLayer.ItemsSource = source;

The rectangles are geographically positioned and when you panning the map they are moved as well so they  always are over the geographical location specified in the code. This is how it should work.

The only difference between List and ObservableCollection is that ObservableCollection raise collection changed event when you add or remove items. Information layer handle this event and draw new or remove old items.

Kind regards,
Andrey Murzov
the Telerik team