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
if ( !(element instanceof IFileEditorInput))
			return super.createElementInfo(element);
			
		IFileEditorInput input= (IFileEditorInput) element;
		ICompilationUnit original= createCompilationUnit(input.getFile());
		if (original != null) {
				
			try {
				
				IProgressMonitor monitor= new NullProgressMonitor();
				
				try {
					input.getFile().refreshLocal(IResource.DEPTH_INFINITE, monitor);
				} catch (CoreException x) {
					handleCoreException(x, JavaEditorMessages.getString("CompilationUnitDocumentProvider.error.createElementInfo")); 
				}
				
				IAnnotationModel m= createCompilationUnitAnnotationModel(input);
				IProblemRequestor r= m instanceof IProblemRequestor ? (IProblemRequestor) m : null;
				ICompilationUnit c= (ICompilationUnit) original.getSharedWorkingCopy(monitor, fBufferFactory, r);
				
				DocumentAdapter a= null;
				try {
					a= (DocumentAdapter) c.getBuffer();
				} catch (ClassCastException x) {
					IStatus status= new Status(IStatus.ERROR, JavaUI.ID_PLUGIN, JavaStatusConstants.TEMPLATE_IO_EXCEPTION, "Shared working copy has wrong buffer", x); 
					throw new CoreException(status);
				}
				
				_FileSynchronizer f= new _FileSynchronizer(input);