I get a ClassCastException when i try to get the selectedItem from ComboBox, the combobox is loaded with a BeanModel, but it appears that the combo return a diferent class with underscores in the package name, like mi_package_name_MiClass
I uploaded the complete source code (netbeans project) in this URL:
www.preparatorianos.com/GXTBugs.rar
And you can see the error running, here:
www.preparatorianos.com/GXTBugs