Bug 63840 warning on unused labels
we have warnings for all sorts of unused things. one for unused labels would be good too.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/ProblemSeveritiesConfigurationBlock.java
addComboBox(inner, label, PREF_15_PB_FINAL_PARAM_BOUND, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_inexact_vararg_label; 
		addComboBox(inner, label, PREF_15_PB_VARARGS_ARGUMENT_NEED_CAST, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_autoboxing_problem_label; 
		addComboBox(inner, label, PREF_15_PB_AUTOBOXING_PROBLEM, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_missing_override_annotation_label; 
		addComboBox(inner, label, PREF_15_PB_MISSING_OVERRIDE_ANNOTATION, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_missing_deprecated_annotation_label; 
		addComboBox(inner, label, PREF_PB_MISSING_DEPRECATED_ANNOTATION, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_annotation_super_interface_label; 
		addComboBox(inner, label, PREF_15_PB_ANNOTATION_SUPER_INTERFACE, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_incomplete_enum_switch_label; 
		addComboBox(inner, label, PREF_15_PB_INCOMPLETE_ENUM_SWITCH, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_unhandled_surpresswarning_tokens;
		addComboBox(inner, label, PREF_PB_UNHANDLED_WARNING_TOKEN, errorWarningIgnore, errorWarningIgnoreLabels, defaultIndent);
		
		label= PreferencesMessages.ProblemSeveritiesConfigurationBlock_pb_enable_surpresswarning_annotation; 
		addCheckBox(inner, label, PREF_PB_SUPPRESS_WARNINGS, enabledDisabled, 0);
		
		IDialogSettings section= JavaPlugin.getDefault().getDialogSettings().getSection(SETTINGS_SECTION_NAME);
		restoreSectionExpansionStates(section);
		
		return sc1;
	}
	
	/* (non-javadoc)
	 * Update fields and validate.