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
fSelectionHistory.setHistoryAction(historyAction);		
		fGenerateActionGroup= new GenerateActionGroup(this, ITextEditorActionConstants.GROUP_EDIT);
		ActionGroup rg= new RefactorActionGroup(this, ITextEditorActionConstants.GROUP_EDIT);
		
		fActionGroups.addGroup(rg);
		fActionGroups.addGroup(fGenerateActionGroup);
		
		
		fContextMenuGroup= new CompositeActionGroup(new ActionGroup[] {
			fGenerateActionGroup, 
			rg, 
			new LocalHistoryActionGroup(this, ITextEditorActionConstants.GROUP_EDIT)});
	}
	/*
	 * @see JavaEditor#getElementAt(int)
	 */
	protected IJavaElement getElementAt(int offset) {
		return getElementAt(offset, true);
	}
	
	/**
	 * Returns the most narrow element including the given offset.  If <code>reconcile</code>
	 * is <code>true</code> the editor's input element is reconciled in advance. If it is 
	 * <code>false</code> this method only returns a result if the editor's input element
	 * does not need to be reconciled.
	 * 
	 * @param offset the offset included by the retrieved element
	 * @param reconcile <code>true</code> if working copy should be reconciled
	 */
	protected IJavaElement getElementAt(int offset, boolean reconcile) {