Failed to load widgetset after project import to Eclipse Mars

Hello Forum,

get following message

Failed to load the widgetset: ./VAADIN/widgetsets/com.vaadin.DefaultWidgetSet/com.vaadin.DefaultWidgetSet.nocache.js?1443879584867

after project import on Eclipse Mars (latest version).

Project came from Eclipse Juno with Vaadin 7.4.6

Made a clean install with Vaadin 7.5.6 and do not have own widgets.

Cleaned the project, resolved the ivy, cleaned caches....

Sitting here since hours do not know what to do.

Simple new created HelloWorld application in this clean installation works.

But importet project not.

What to do?

Is there no project migration information sheet for tasks like that?
At the moment do not kwow if  Eclipse Mars is a recommended version...

If looks like you don't have com.vaadin:vaadin-client-compiled on you classpath. That module contains the bare bones widgetset with only those client side implmenentations that come with the core. You chould somehow add that to your classpath (ivy.xml). In Maven you'd add this to your pom.xml:

<dependency>
               <groupId>com.vaadin</groupId>
               <artifactId>vaadin-client-compiled</artifactId>
          </dependency>

(possibly with version tag)

cheers,
matti