Bug 166315 Combo box doesn't allow blank when set string type in parameter editor
Combo box doesn't allow blank when set string type in parameter editor Steps to reproduce: 1.New a parameter, display type is Combo Box 2.Select data type as String Expected result: "Allow blank values" is enable. Actual result: "Allow blank values" is gray and can't be checked.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
if ( allowBlank.isEnabled( ) )
			{
				if ( dirtyProperties.containsKey( CHECKBOX_ALLOW_BLANK ) )
				{
					inputParameter.setAllowBlank( getProperty( CHECKBOX_ALLOW_BLANK ) );
				}
			}
			else
			{
				inputParameter.setProperty( ScalarParameterHandle.ALLOW_BLANK_PROP,
						null );
			}
			if ( doNotEcho.isEnabled( ) )
			{
				if ( dirtyProperties.containsKey( CHECKBOX_DO_NOT_ECHO ) )
				{
					inputParameter.setConcealValue( getProperty( CHECKBOX_DO_NOT_ECHO ) );
				}
			}
			else
			{
				inputParameter.setProperty( ScalarParameterHandle.CONCEAL_VALUE_PROP,
						null );
			}
			if ( needSort.isEnabled( ) )
			{
				if ( dirtyProperties.containsKey( CHECKBOX_SORT ) )
				{
					inputParameter.setFixedOrder( !getProperty( CHECKBOX_SORT ) );
				}