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
f.install();
				
				CompilationUnitInfo info= new CompilationUnitInfo(a.getDocument(), m, f, c);
				info.setModificationStamp(computeModificationStamp(input.getFile()));
				info.fStatus= a.getStatus();
				
				if (r instanceof IProblemRequestorExtension) {
					IProblemRequestorExtension extension= (IProblemRequestorExtension) r;
					extension.setIsActive(isHandlingTemporaryProblems());
				}
				m.addAnnotationModelListener(fGlobalAnnotationModelListener);
				
				return info;
				
			} catch (JavaModelException x) {
				throw new CoreException(x.getStatus());
			}
		} else {		
			return super.createElementInfo(element);
		}
	}
	
	/*
	 * @see AbstractDocumentProvider#disposeElementInfo(Object, ElementInfo)
	 */
	protected void disposeElementInfo(Object element, ElementInfo info) {
		
		if (info instanceof CompilationUnitInfo) {
			CompilationUnitInfo cuInfo= (CompilationUnitInfo) info;
			cuInfo.fCopy.destroy();