Vaadin Portlet and Liferay

Hi all, please i need help.

We have a instance of liferay with multilanguaghe support. I write Vaadin Portlet and integrathed to portal. Portlet works fine. But after i change language and portlet was reloaded, so when i etc. open dialog from portlet or basic command ( on buttonclick add item to list ) so portlet app crash. BUT when i clean browser cache (in firefox shift+alt+delete) and refresh page so portlet works! Some standing in browswer cache after language change and portlet can´t works. Same result is when i back on previous language, portlet works. I tried set u friendly URL on Liferay but any result. Clean browser result from portlet code (javascript) is inpossible

Please can you tell me somebody where is problem?

Thank you very much…, and so sorry for my english