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/JavaReplaceWithEditionAction.java
ITypedElement target= new JavaTextBufferNode(buffer, inEditor);
			ITypedElement[] editions= buildEditions(target, file);
			ITypedElement ti= null;
			if (fPrevious)
				ti= d.selectPreviousEdition(target, editions, input);
			else
				ti= d.selectEdition(target, editions, input);
						
			if (ti instanceof IStreamContentAccessor) {
														
				
				String[] lines= null;
				try {
					lines= JavaCompareUtilities.readLines(((IStreamContentAccessor) ti).getContents());								
				} catch (CoreException ex) {
					JavaPlugin.log(ex);
				}
				if (lines == null) {
					MessageDialog.openError(shell, errorTitle, errorMessage);
					return;
				}
				
				MemberEdit edit= new MemberEdit(input, MemberEdit.REPLACE, lines,
										CodeFormatterPreferencePage.getTabSize());
				edit.setAddLineSeparators(false);
										
				IProgressMonitor nullProgressMonitor= new NullProgressMonitor();
				
				TextBufferEditor editor= new TextBufferEditor(buffer);