Crash by drag and drop in QTreeView with QFileSystemModel+QSortFilterProxyModel

#include <QApplication>
#include <QTreeView>
#include <QDebug>
#include <QMainWindow>
#include <QFileSystemModel>
#include <QSortFilterProxyModel>

int main(int argc, char* argv[]) {
  QApplication app(argc, argv);

  QTreeView tree;
  tree.setSelectionMode(QAbstractItemView::ExtendedSelection);
  tree.setDragEnabled(true);
  tree.setAcceptDrops(true);
  tree.setDropIndicatorShown(true);
  tree.setDragDropMode(QAbstractItemView::InternalMove);

  QString dirPath = QDir::homePath();
  QFileSystemModel* model = new QFileSystemModel();
  model->setReadOnly(false);
  model->setRootPath(dirPath);

  QSortFilterProxyModel* filter = new QSortFilterProxyModel;
  filter->setSourceModel(model);
  tree.setModel(filter);

  QDir parentDir(dirPath);
  parentDir.cdUp();
  QModelIndex rootIndex = filter->mapFromSource(model->index(parentDir.absolutePath()));
  tree.setRootIndex(rootIndex);

  QMainWindow win1;
  win1.show();
  QMainWindow win2;
  win2.setCentralWidget(&tree);
  win2.show();

  win1.setFocus();
  win2.setFocus();

  return app.exec();
}

Process:         QtTest [2283]
Path:            /Users/USER/*/QtTest.app/Contents/MacOS/QtTest
Identifier:      ???
Version:         ??? (???)
Code Type:       X86-64 (Native)
Parent Process:  Qt Creator [555]
Responsible:     Qt Creator [555]
User ID:         501

Date/Time:       2015-01-13 16:30:39.632 +0900
OS Version:      Mac OS X 10.9.5 (13F34)
Report Version:  11
Anonymous UUID:  2065E299-2305-4E16-A4DB-D8EF3CFFFAC7


Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000

VM Regions Near 0:
--> 
    __TEXT                 0000000104f18000-0000000104f23000 [   44K] r-x/rwx SM=COW  /Users/USER/*/QtTest.app/Contents/MacOS/QtTest

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   org.qt-project.QtCore         	0x0000000105dbcd74 QSortFilterProxyModelPrivate::proxy_to_source(QModelIndex const&) const + 244
1   org.qt-project.QtCore         	0x0000000105dc6b22 QSortFilterProxyModel::mapToSource(QModelIndex const&) const + 18
2   org.qt-project.QtCore         	0x0000000105dc4749 QSortFilterProxyModel::data(QModelIndex const&, int) const + 41
3   org.qt-project.QtWidgets      	0x00000001051ad98b QAccessibleTableCell::state() const + 347
4   libqcocoa.dylib               	0x0000000108a2587a QCocoaAccessible::hasValueAttribute(QAccessibleInterface*) + 58
5   libqcocoa.dylib               	0x0000000108a2244e -[QMacAccessibilityElement accessibilityAttributeNames] + 398
6   com.apple.AppKit              	0x00007fff925bdf3f -[NSObject(NSAccessibilityInternal) _accessibilityAttributeNamesClientError:] + 67
7   com.apple.AppKit              	0x00007fff925bf6b1 CopyAttributeNames + 216
8   com.apple.HIServices          	0x00007fff91157c96 _AXXMIGCopyAttributeNames + 200
9   com.apple.HIServices          	0x00007fff91161204 _XCopyAttributeNames + 409
10  com.apple.HIServices          	0x00007fff911408f4 mshMIGPerform + 211
11  com.apple.CoreFoundation      	0x00007fff8829c829 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 41
12  com.apple.CoreFoundation      	0x00007fff8829c79e __CFRunLoopDoSource1 + 478
13  com.apple.CoreFoundation      	0x00007fff8828d7d6 __CFRunLoopRun + 1830
14  com.apple.CoreFoundation      	0x00007fff8828ce75 CFRunLoopRunSpecific + 309
15  com.apple.HIToolbox           	0x00007fff86496a0d RunCurrentEventLoopInMode + 226
16  com.apple.HIToolbox           	0x00007fff864967b7 ReceiveNextEventCommon + 479
17  com.apple.HIToolbox           	0x00007fff864965bc _BlockUntilNextEventMatchingListInModeWithFilter + 65
18  com.apple.AppKit              	0x00007fff9223e24e _DPSNextEvent + 1434
19  com.apple.AppKit              	0x00007fff9223d89b -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 122
20  com.apple.AppKit              	0x00007fff9223199c -[NSApplication run] + 553
21  libqcocoa.dylib               	0x0000000108a0f92d QCocoaEventDispatcher::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 2189
22  org.qt-project.QtCore         	0x0000000105dec5ad QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 381
23  org.qt-project.QtCore         	0x0000000105def58a QCoreApplication::exec() + 346
24                                	0x0000000104f1aad9 main + 825 (main.cpp:41)
25  libdyld.dylib                 	0x00007fff88a2b5fd start + 1