Binding classes do not support the "group" attribute. Here's the relevant code (using Griffon):
textField(text: bind(target: model.currentRecord, 'count',
When run, produces "No such property: group for class: groovy.swing.binding.JTextComponentTextBinding". From Andres Almiray of Griffon:
"The problem appears to be in BindFactory.groovy:321, where the group: attribute is set on the binding instance, which may or may nor support he property (in this case it does not). this is certainly a bug in BindFactory ..."