If you use radio channel mappings, and save your settings at least twice, when you subsequently enter WebEPG section in SetupTV, some settings are reset to defaults and radio mappings are empty. An exception "System.ArgumentException: An item with the same key has already been added" is logged and WebEPG.xml grows each time you save your settings.

h4. Steps to Reproduce
1. Enter SetupTV and navigate to WebEPG section.
2. Configure all settings and make sure you have entries in Radio Mappings.
3. Save your settings twice (press the save button)
4. Restart SetupTV and navigate to WebEPG section.
5. Most settings are reset to defaults and Radio Mappings is empty.

h4. Additional Information
Reported in http://forum.team-mediaportal.com/webepg-136/webepg-one-day-behind-71330/#post520071 by Henning
Confirmed by Arion_p