i am playing little bit with Replication feature. I notices that there is one major bug related to model validator - model validator on Client is registered to validation engine multiple times instead of once. I think this is not bug in Implementation of ExportModelValidator, but ModelValidatorEngine, because it looks like model validators are not removed from validation engine when user changes role or log out, but when user is logged again. validator is registers again too.
Steps to reproduce:
1. In Client window set org.adempiere.ExportModelValidator as model validation class
2. Rester your server to apply this change
3. Login into system
4. Change role and log in with same credentials
These steps cause that one Model Validator is registered multiple times in Model Validation Engine and modelChange method is executed multiple times = BUG.
Bug can be also seen when you try to debug addModelChange method of ModelValidationEngine class.