@Nullable
 public MoveDestination selectDirectory(
     final PackageWrapper targetPackage, final boolean showChooserWhenDefault) {
   final DirectoryChooser.ItemWrapper selectedItem =
       (DirectoryChooser.ItemWrapper) getComboBox().getSelectedItem();
   if (selectedItem == null || selectedItem == NULL_WRAPPER) {
     return new MultipleRootsMoveDestination(targetPackage);
   }
   final PsiDirectory selectedPsiDirectory = selectedItem.getDirectory();
   VirtualFile selectedDestination = selectedPsiDirectory.getVirtualFile();
   if (showChooserWhenDefault
       && selectedDestination == myInitialTargetDirectory.getVirtualFile()
       && mySourceRoots.length > 1) {
     selectedDestination =
         MoveClassesOrPackagesUtil.chooseSourceRoot(
             targetPackage, mySourceRoots, myInitialTargetDirectory);
   }
   if (selectedDestination == null) return null;
   return new AutocreatingSingleSourceRootMoveDestination(targetPackage, selectedDestination);
 }
 private void setComboboxModel(
     final JComboBox comboBox,
     final VirtualFile initialTargetDirectorySourceRoot,
     final VirtualFile oldSelection,
     final ProjectFileIndex fileIndex,
     final VirtualFile[] sourceRoots,
     final Project project,
     final boolean forceIncludeAll,
     final Pass<String> updateErrorMessage) {
   final LinkedHashSet<PsiDirectory> targetDirectories = new LinkedHashSet<PsiDirectory>();
   final HashMap<PsiDirectory, String> pathsToCreate = new HashMap<PsiDirectory, String>();
   MoveClassesOrPackagesUtil.buildDirectoryList(
       new PackageWrapper(PsiManager.getInstance(project), getTargetPackage()),
       sourceRoots,
       targetDirectories,
       pathsToCreate);
   if (!forceIncludeAll && targetDirectories.size() > pathsToCreate.size()) {
     targetDirectories.removeAll(pathsToCreate.keySet());
   }
   final ArrayList<DirectoryChooser.ItemWrapper> items =
       new ArrayList<DirectoryChooser.ItemWrapper>();
   DirectoryChooser.ItemWrapper initial = null;
   DirectoryChooser.ItemWrapper oldOne = null;
   for (PsiDirectory targetDirectory : targetDirectories) {
     DirectoryChooser.ItemWrapper itemWrapper =
         new DirectoryChooser.ItemWrapper(targetDirectory, pathsToCreate.get(targetDirectory));
     items.add(itemWrapper);
     final VirtualFile sourceRootForFile =
         fileIndex.getSourceRootForFile(targetDirectory.getVirtualFile());
     if (sourceRootForFile == initialTargetDirectorySourceRoot) {
       initial = itemWrapper;
     } else if (sourceRootForFile == oldSelection) {
       oldOne = itemWrapper;
     }
   }
   items.add(NULL_WRAPPER);
   final DirectoryChooser.ItemWrapper selection =
       chooseSelection(initialTargetDirectorySourceRoot, fileIndex, items, initial, oldOne);
   final ComboBoxModel model = comboBox.getModel();
   if (model instanceof CollectionComboBoxModel) {
     boolean sameModel = model.getSize() == items.size();
     if (sameModel) {
       for (int i = 0; i < items.size(); i++) {
         final DirectoryChooser.ItemWrapper oldItem =
             (DirectoryChooser.ItemWrapper) model.getElementAt(i);
         final DirectoryChooser.ItemWrapper itemWrapper = items.get(i);
         if (!areItemsEquivalent(oldItem, itemWrapper)) {
           sameModel = false;
           break;
         }
       }
     }
     if (sameModel) {
       if (areItemsEquivalent(
           (DirectoryChooser.ItemWrapper) comboBox.getSelectedItem(), selection)) {
         return;
       }
     }
   }
   updateErrorMessage(updateErrorMessage, fileIndex, selection);
   Collections.sort(
       items,
       new Comparator<DirectoryChooser.ItemWrapper>() {
         @Override
         public int compare(DirectoryChooser.ItemWrapper o1, DirectoryChooser.ItemWrapper o2) {
           if (o1 == NULL_WRAPPER) return -1;
           if (o2 == NULL_WRAPPER) return 1;
           return o1.getRelativeToProjectPath().compareToIgnoreCase(o2.getRelativeToProjectPath());
         }
       });
   comboBox.setModel(new CollectionComboBoxModel(items, selection));
 }