Bug 28698 Ctrl+O (show outline) does not work if the file being shown in the editor is read only
M4 The summary tells all. Works if the file is not read only. Is this by design?
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
Shell shell= getSite().getShell();
				MessageDialog.openError(shell, JavaEditorMessages.getString("CompilationUnitEditor.error.saving.title1"), JavaEditorMessages.getString("CompilationUnitEditor.error.saving.message1")); 
			}
			
		} else {	
			
			setStatusLineErrorMessage(null);
			
			IWorkingCopyManager manager= JavaPlugin.getDefault().getWorkingCopyManager();
			ICompilationUnit unit= manager.getWorkingCopy(getEditorInput());
			
			if (unit != null) {
				synchronized (unit) { 
					performSaveOperation(createSaveOperation(false), progressMonitor); 
				}
			} else 
				performSaveOperation(createSaveOperation(false), progressMonitor);
		}
	}
	
	/**
	 * Asks the user if it is ok to store in non-workbench encoding.
	 * @return <true> if the user wants to continue
	 */
	private boolean askIfNonWorkbenchEncodingIsOk() {
		IDocumentProvider provider= getDocumentProvider();
		if (provider instanceof IStorageDocumentProvider) {
			IEditorInput input= getEditorInput();
			IStorageDocumentProvider storageProvider= (IStorageDocumentProvider)provider;
			String encoding= storageProvider.getEncoding(input);