Bug 179743 Parameter Validate Event is not Called
I have tested the validate event on parameters and it never appears to get called.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java
{
					if ( !visitCascadingParamterGroup(
							(CascadingParameterGroupHandle) param, value ) )
					{
						return false;
					}
				}
				else if ( param instanceof ParameterGroupHandle )
				{
					if ( !visitParameterGroup( (ParameterGroupHandle) param,
							value ) )
					{
						return false;
					}
				}
				else if ( param instanceof ScalarParameterHandle )
				{
					if ( !visitScalarParameter( (ScalarParameterHandle) param,
							value ) )
					{
						return false;
					}
				}
			}
			return true;
		}
		boolean visitCascadingParamterGroup(
				CascadingParameterGroupHandle group, Object value )
		{
			return visitParameterGroup( group, value );