Bug 17699 Java Editor: Local Histroy menu entries are enabled for read-only files
F1 - make file read-only - open it - observe: context menu contains Local History actions. Only compare makes sense for read-only files
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/compare/JavaAddElementFromHistory.java
}
				
		boolean inEditor= beingEdited(file);
		if (inEditor) {
			parent= (IParent) getWorkingCopy((IJavaElement)parent);
			if (input != null)
				input= (IMember) getWorkingCopy(input);
		}
		
		TextBuffer buffer= null;
		try {
			buffer= TextBuffer.acquire(file);
		
			
			ITypedElement target= new JavaTextBufferNode(buffer, inEditor);
			ITypedElement[] editions= buildEditions(target, file);
											
			ResourceBundle bundle= ResourceBundle.getBundle(BUNDLE_NAME);
			EditionSelectionDialog d= new EditionSelectionDialog(shell, bundle);
			d.setAddMode(true);
			ITypedElement ti= d.selectEdition(target, editions, parent);
			if (!(ti instanceof IStreamContentAccessor))
				return;	
			
			
			String[] lines= null;
			try {
				lines= JavaCompareUtilities.readLines(((IStreamContentAccessor) ti).getContents());								
			} catch (CoreException ex) {
				JavaPlugin.log(ex);