Bug 19014 Empty CU after reorg
F2 - enable single click and show in members in packages view - open TestCase.java in editor - give focus to packages view - change it on disk - copy a method in TestCase using DnD - activate the TestCase.java editor - answer question with no - activate revert from context menu observe: CU is empty
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitDocumentProvider.java
private IDocument internalGetDocument(IFileEditorInput input) throws CoreException {
				IDocument document= getDocument(input);
				if (document != null)
					return document;
				return CompilationUnitDocumentProvider.this.createDocument(input);
			}
			
			public IBuffer createBuffer(IOpenable owner) {
				if (owner instanceof ICompilationUnit) {
					
					ICompilationUnit unit= (ICompilationUnit) owner;
					
					try {
						
						ICompilationUnit original= (ICompilationUnit) unit.getOriginalElement();
						IResource resource= original.getCorrespondingResource();
						if (resource instanceof IFile) {
							IFileEditorInput providerKey= new FileEditorInput((IFile) resource);
							
							IDocument document= null;
							IStatus status= null;
							
							try {
								document= internalGetDocument(providerKey);
							} catch (CoreException x) {
								status= x.getStatus();
								document= new Document();