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
public void doSave(IProgressMonitor progressMonitor) {
		
		IDocumentProvider p= getDocumentProvider();
		if (p == null) {
			
			return;
		}
			
		if (!askIfNonWorkbenchEncodingIsOk()) {
			progressMonitor.setCanceled(true);
			return;
		}
		
		if (p.isDeleted(getEditorInput())) {
			
			if (isSaveAsAllowed()) {
				
				/*
				 * 1GEUSSR: ITPUI:ALL - User should never loose changes made in the editors.
				 * Changed Behavior to make sure that if called inside a regular save (because
				 * of deletion of input element) there is a way to report back to the caller.
				 */
				 performSaveAs(progressMonitor);
			
			} else {
				
				/* 
				 * 1GF5YOX: ITPJUI:ALL - Save of delete file claims it's still there
				 * Missing resources.
				 */