I have found a bug in snapping functionality with the following error:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at com.esri.ags.tools::DrawTool/checkForSnapping()
at com.esri.ags.tools::DrawTool/map_mouseMoveFirstHandler()
Yes, the version of ArcGIS API for Flex is 2.4.
This problem occurs if there is any Graphic object with null geometry in any GraphicsLayer in the Map. If this happens, the snapping does not work.
You can reproduce this problem using MXML attached.
Regards,
Matej Vrtich