Bug 33040 No single Undo for generate delegate methods
RC 1 - JUnit setup - open TestCase - select fName - generate delegate methods for all String methods - press Ctrl+Z Observe: only one method is removed.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/AddDelegateMethodsAction.java
for (int i = 0; i < fields.length; i++) {
			if (!hasPrimitiveType(fields[i]) || isArray(fields[i])) {
				count++;
			}
		}
		return (count > 0);
	}
	/*
	 * Returns fields in the selection or <code>null</code> if the selection is 
	 * empty or not valid.
	 */
	private IField[] getSelectedFields(IStructuredSelection selection) {
		List elements = selection.toList();
		int nElements = elements.size();
		if (nElements > 0) {
			IField[] res = new IField[nElements];
			ICompilationUnit cu = null;
			for (int i = 0; i < nElements; i++) {
				Object curr = elements.get(i);
				if (curr instanceof IField) {
					IField fld = (IField) curr;
					if (i == 0) {
						
						cu = fld.getCompilationUnit();
						if (cu == null) {
							return null;
						}
					} else if (!cu.equals(fld.getCompilationUnit())) {
						
						return null;