performance of calendar with many many events

Hi

I use the vaadin calendar for display a week of events.

When I load my 820 events, Mozilla/IE take many long seconds to display my view (>8 seconds)

I work with vaadin 7.1.15 and I load my Calendar component with a BeanItemContainer.

The big part of the loading concerns unstacking of json elements and execution of js on them.

Have you many ideas to optimize my loading time ?

Best regards
Vincent