MouseLeftButtonUp="FeatureLayer_MouseLeftButtonUp"
MouseClick="QueryPoint_MouseClick"
If MouseLeftButtonDown is marked e.Handled = true, MouseLeftButtonUp will not fire. Draw and Editor when enabled may be listening to the same events.
You can use the same Map.MouseClick event to perform your selection and identify. The following SDK sample, shows you how you can get the graphics from a MouseClick event: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#InfoWindowSimple