Bug 182673 No default value error message prompts incorrectly
Steps to reproduce: 1. New a report parameter; 2. Choose control type as Combo; 3. Choose parameter as dynamic type; Expected result: As the isRequired is false by default, parameter's default value can be null value. There should be no error message about no default value prompt. Actual result; Error messages prompts
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
{
		}
		public void dispose( )
		{
		}
		public boolean isLabelProperty( Object element, String property )
		{
			return false;
		}
		public void removeListener( ILabelProviderListener listener )
		{
		}
	};
	private ICellModifier cellModifier = new ICellModifier( ) {
		public boolean canModify( Object element, String property )
		{
			if ( element != selectedParameter )
			{
				return false;
			}
			if ( property.equals( COLUMN_NAME ) )
			{
				return true;
			}
			if ( COLUMN_DATA_SET.equals( property ) )
			{
				if ( isSingle( ) && getFirstParameter( ) != element )
				{
					return false;
				}