happen crash when switching to histogram layout

[grimmer0125]

not always reproduce
I trid

1. cube_x220_z100_17MB.fits
2. switch to profiler layout, then play around its setting.
3. switch to histogram layout. then crash

crash:
Process:               CARTA [3993]
Path:                  /Applications/CARTA.app/Contents/MacOS/./CARTA
Identifier:            com.apple.ScriptEditor.id.Carta
Version:               0.9 (???)
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           CARTA [3993]
User ID:               501

PlugIn Path:             /Applications/CARTA.app/Contents/Frameworks/libcore.1.dylib
PlugIn Identifier:       libcore.1.dylib
PlugIn Version:          ??? (0)

Date/Time:             2017-10-26 19:38:51.514 +0800
OS Version:            Mac OS X 10.12.6 (16G29)
Report Version:        12
Anonymous UUID:        03779B5C-DEEC-F0FF-6154-B82B00C4847B

Sleep/Wake UUID:       AD5DEF87-8540-4810-A5E4-036C08E6369F

Time Awake Since Boot: 62000 seconds
Time Since Wake:       1800 seconds

System Integrity Protection: enabled

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

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000018
Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Segmentation fault: 11
Termination Reason:    Namespace SIGNAL, Code 0xb
Terminating Process:   exc handler [0]

VM Regions Near 0x18:
--> 
    __TEXT                 000000010df76000-000000010df8f000 [  100K] r-x/rwx SM=COW  /Applications/CARTA.app/Contents/MacOS/CARTA

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libcore.1.dylib                   0x000000010dfc6cb4 Carta::State::StateInterface::getArraySize(QString const&) const + 4
1   libcore.1.dylib                   0x000000010e0d4149 Carta::Data::Profiler::setSelectedRegion(QString const&) + 121
2   libcore.1.dylib                   0x000000010e0e00d9 std::__1::__function::__func<Carta::Data::Profiler::_initializeCallbacks()::$_26, std::__1::allocator<Carta::Data::Profiler::_initializeCallbacks()::$_26>, QString (QString const&, QString const&, QString const&)>::operator()(QString const&, QString const&, QString const&) + 217
3   CARTA                             0x000000010df84628 std::__1::__function::__func<DesktopConnector::jsSendCommandSlot(QString const&, QString const&)::$_1, std::__1::allocator<DesktopConnector::jsSendCommandSlot(QString const&, QString const&)::$_1>, void ()>::operator()() + 136
4   org.qt-project.QtCore             0x000000010f3f8cc1 QObject::event(QEvent*) + 801
5   org.qt-project.QtWidgets          0x000000010e62f60d QApplicationPrivate::notify_helper(QObject*, QEvent*) + 301
6   org.qt-project.QtWidgets          0x000000010e6309b1 QApplication::notify(QObject*, QEvent*) + 369
7   org.qt-project.QtCore             0x000000010f3cef84 QCoreApplication::notifyInternal2(QObject*, QEvent*) + 164
8   org.qt-project.QtCore             0x000000010f3cffab QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) + 891
9   libqcocoa.dylib                   0x00000001154de30e 0x1154b9000 + 152334
10  libqcocoa.dylib                   0x00000001154debd1 0x1154b9000 + 154577
11  com.apple.CoreFoundation          0x00007fff894eb321 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
12  com.apple.CoreFoundation          0x00007fff894cc21d __CFRunLoopDoSources0 + 557
13  com.apple.CoreFoundation          0x00007fff894cb716 __CFRunLoopRun + 934
14  com.apple.CoreFoundation          0x00007fff894cb114 CFRunLoopRunSpecific + 420
15  com.apple.HIToolbox               0x00007fff88a2bebc RunCurrentEventLoopInMode + 240
16  com.apple.HIToolbox               0x00007fff88a2bcf1 ReceiveNextEventCommon + 432
17  com.apple.HIToolbox               0x00007fff88a2bb26 _BlockUntilNextEventMatchingListInModeWithFilter + 71
18  com.apple.AppKit                  0x00007fff86fc4a54 _DPSNextEvent + 1120
19  com.apple.AppKit                  0x00007fff877407ee -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 2796
20  com.apple.AppKit                  0x00007fff86fb93db -[NSApplication run] + 926
21  libqcocoa.dylib                   0x00000001154dd933 0x1154b9000 + 149811
22  org.qt-project.QtCore             0x000000010f3cb291 QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 417
23  org.qt-project.QtCore             0x000000010f3cf5f7 QCoreApplication::exec() + 343
24  CARTA                             0x000000010df7f533 int Carta::Core::coreMain<DesktopPlatform>(QString, int, char**) + 979
25  CARTA                             0x000000010df7f0d5 main + 53
26  libdyld.dylib                     0x00007fff9ec4b235 start + 1