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/ParameterDialog.java
}
				}
			}
			else if ( DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( getSelectedControlType( ) ) )
			{
				if ( getSelectedDataType( ).equals( DesignChoiceConstants.PARAM_TYPE_STRING ) )
				{
					if ( defaultValue == null )
					{
						defaultValueChooser.select( 0 );
					}
					else if ( defaultValue.equals( "" ) )
					{
						defaultValueChooser.select( 1 );
					}
					else
					{
						defaultValueChooser.setText( defaultValue );
					}
				}
				else if ( defaultValue != null )
				{
					if ( ( defaultValue.equals( Boolean.toString( true ) ) || defaultValue.equals( Boolean.toString( false ) ) ) )
					{
						defaultValue = null;
					}
					else
					{
						defaultValueChooser.setText( defaultValue );
					}