Hi
I just found this error is present after upgrading to 3.7.3 from 3.7.1. It happens when I drag across objects with an UIEventTrigger component, which can accidentally happen a lot on mobile devices

Failed to call function OnDragEnd of class UIEventTrigger
Calling function OnDragEnd with no parameters but the function requires 1.
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UICamera:Notify(GameObject, String, Object) (at Assets/NGUI/Scripts/UI/UICamera.cs:1065)
UICamera:ProcessTouch(Boolean, Boolean) (at Assets/NGUI/Scripts/UI/UICamera.cs:1768)
UICamera:ProcessMouse() (at Assets/NGUI/Scripts/UI/UICamera.cs:1402)
UICamera:ProcessTouches() (at Assets/NGUI/Scripts/UI/UICamera.cs:1474)
UICamera:Update() (at Assets/NGUI/Scripts/UI/UICamera.cs:1221)
Failed to call function OnDragStart of class UIEventTrigger
Calling function OnDragStart with no parameters but the function requires 1.
UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
UICamera:Notify(GameObject, String, Object) (at Assets/NGUI/Scripts/UI/UICamera.cs:1065)
UICamera:ProcessTouch(Boolean, Boolean) (at Assets/NGUI/Scripts/UI/UICamera.cs:1720)
UICamera:ProcessMouse() (at Assets/NGUI/Scripts/UI/UICamera.cs:1402)
UICamera:ProcessTouches() (at Assets/NGUI/Scripts/UI/UICamera.cs:1474)
UICamera:Update() (at Assets/NGUI/Scripts/UI/UICamera.cs:1221)
Looks like the inspector for UIEventTrigger do not cater OnDragStart and OnDragEnd, maybe this is the problem??