IConfigurationElement[] targetEditors= element.getChildren(TARGET_EDITOR);
IConfigurationElement[] targetContentTypes= element.getChildren(TARGET_CONTENT_TYPE);
IConfigurationElement[] targetClasses= element.getChildren(TARGET_CLASS);
if (targetContentTypes.length + targetEditors.length + targetClasses.length == 0) {
helper.fail(RulerColumnMessages.RulerColumnDescriptor_missing_target_msg);
fTarget= null; // dummy
} else {
RulerColumnTarget combined= null;
for (int i= 0; i < targetEditors.length; i++) {
IConfigurationElement targetEditor= targetEditors[i];