I think the problem is as “simple” as the GWT compiler expecting the VTestPanel class to be in a *.gwt.client.ui package. So moving that class to com.test
.gwt. client.ui should allow it to compile.
The source path for GWT indicates a sub-path under the package/directory where the GWT module is. Therefore, GWT is looking for your client side implementation in com.test.com.test instead of com.test.client .
You usually don’t need an explicit source path as the default is “client”, which matches the recommended project structure. You just need to make sure the class path given to the GWT compiler includes the necessary source (root) directories.
Note that the 6.2 widgetset compilation uses a widgetset generator (referenced from DefaultWidgetSet) that, among other things, can automatically manage your .gwt.xml file by adding or removing GWT modules on your classpath, including in add-on JARs. Therefore, you rarely need to adjust the GWT module by hand when using 6.2 - just running the compiler will create or modify the file as needed.
After I removed the source node from the module file the compiling now succeeded. I’m not sure what it prevented the first time. I had added the source node because the compiler gave the warning without it too.