Finally I found with your respond but I found a bug.
First my error was that I use widget list option that you said that it don’t display the refresh.
The other thing is tha the update give me this error
Saving….
Error validating list options input
AmR iCal Events List 2.9.4
Select a list type
press “update” button… it update well
if you press “update” button again it give the error so it don’t update.
thanks for the link, I found lots of usefull information on your website
eric