Hi,
the validation should be done not on widget level but on the whole model level. In case of the random generator which is in the VM dialog, it should be validated in the UnitVmModel (the backing model of all the VM-like entities) and inside it in the validate() method. Than this validate() returns true/false if it is valid / invalid. And than the corresponding list model (VmListModel.onSaveVm() for example) calls the validate and only if it passes it should continue to send the data to server.
Is this not what happens?
Tomas