When RadMap is used within a popup and the map provider is assigned each time before the popup is opened then UI hangs when it is opened second time.

Workaround:

The problem occurs when the RadMap.Provider property is assigned second time when the popup is opened and then it is closed. You can assign this property one time only to avoid this problem. You can do it from a XAML code. Or you can check that the provider is already assigned in the codebehind like following:

private void MapButton_Click(object sender, RoutedEventArgs e)
{
    if (radMap1.Provider == null)
    {
        radMap1.Provider = new OpenStreetMapProvider();
    }
 
    PopupPosition.IsOpen = true;
}

1. If you make two single mouse clicks fast enough, they will be incorrectly interpreted as double click, no matter how far one click from another. And you will be zoomed to the place of the first click.
 
2. Also there is another rated issue with fast map scrolling.
 If I'm at 16 zoom and want to scroll map to other city to the left (without zooming out). To do this I will need to mouse-down at the left edge, then move to the right, then mouse-up near right edge. If you repeating this fast enough, most times you get zoomed in instead of map moving.

Steps to reproduce:
For example, here - http://demos.telerik.com/silverlight/#Map/GeoImageryProviders
 
Just click to Sofia, then quickly click to Bucharest. Map will be zoomed in to Sofia instead of moving to Bucharest.
Quickly = in 200-300ms.

When you draw a MapPolygon with one of his points as 90 latitude then the memory keeps increasing and the application crashes.

The map control should validate locations to prevent using coordinates which do not correspond to the used map projection.

When application has two radwindows, each with a radmap with MaPpolyLine, then the polyline disappears after click in the one window.

When the RadPane that contains the RadMap is redocked to another location then the RadMap locks the browser.
The RadMap loses its data context and gets null into Provider property. When the data context is restored and the RadMap gets its provider then it hangs, because all calculations inside its logic require map provider which contains necessary information about current projection.It is no problem to change map provider from one to another, but the problem occurs when the map provider is changed to null. 
At least the RadMap should raise exception in a case when the Provider property is assigned to null.

We have created an application where a map fills most of the page, but we also have menus on the left and right side that will open and close depending on what the user is doing. In some cases the user will want to keep one or both the menus open all the time, so we have also provided the possibility to pin the menus.

The problem is that when the menus are pinned, we also change the size of the map, and when we do this any shapes that are drawn on the map disappear. We can make them reappear by zooming in or out, and this is only a problem when UseSpringAnimations is set to false, as setting this to true makes the map force some zoom action.

RadMap with Clustering enabled on Visualization layer. Pushpins whose locations have equal or almost equal Latitudes or Longitudes are shown on particular zoom level (for example 19). You see them when clicking on the cluster. If the MaxZoomLEvel is set to be lower than 19, the pushpins are not placed in their correct positions after clicking on clusters and zooming out with mouse multiple times.

RadMaps Silverlight BingMap provider stopped displaying tiles in 2022 due to change in Bing Maps service.

Check notes here:

https://docs.microsoft.com/en-us/answers/questions/799630/arcgis-map-services-stopped-loading.html

Either workaround or statement regarding the future of this feature is needed.