I recently closed this bug, but it started happening again. I suppose the bug is with Qtcurve because with breeze style or other style it doesn't happen. I am using qtcurve qt5 1.8.19 git with latest commit from 11th of August. 

Reproducible: Always

Steps to Reproduce:
1. Reload systemsettings by launching it again.
2.
3.



------------------------------------------------backtrace--------------------------------------------------------------
Application: systemsettings5 (systemsettings5), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7faab9055780 (LWP 2341))]

Thread 2 (Thread 0x7faaa630c700 (LWP 2342)):
#0  0x00007faab4db649d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007faab172a3c2 in poll (__timeout=-1, __nfds=1, __fds=0x7faaa630bd40) at /usr/include/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0x14e28f0, cond=cond@entry=0x14e2930, vector=vector@entry=0x0, count=count@entry=0x0) at xcb_conn.c:479
#3  0x00007faab172c10f in xcb_wait_for_event (c=0x14e28f0) at xcb_in.c:693
#4  0x00007faaa8897389 in QXcbEventReader::run (this=0x14f5a00) at qxcbconnection.cpp:1337
#5  0x00007faab54b5859 in QThreadPrivate::start (arg=0x14f5a00) at thread/qthread_unix.cpp:344
#6  0x00007faab0e9d734 in start_thread (arg=0x7faaa630c700) at pthread_create.c:334
#7  0x00007faab4dbed3d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7faab9055780 (LWP 2341)):
[KCrash Handler]
#6  compare_exchange_strong (__m2=std::memory_order_acquire, __m1=std::memory_order_acquire, __p2=0x1, __p1=@0x7ffd1c1a7c80: 0x0, this=<optimized out>) at /usr/include/c++/4.8/bits/atomic_base.h:844
#7  compare_exchange_strong (__p2=0x1, __m=std::memory_order_acquire, __p1=@0x7ffd1c1a7c80: 0x0, this=<optimized out>) at /usr/include/c++/4.8/atomic:445
#8  testAndSetAcquire<QMutexData*> (currentValue=<synthetic pointer>, newValue=0x1, expectedValue=0x0, _q_value=...) at ../../src/corelib/arch/qatomic_cxx11.h:165
#9  testAndSetAcquire (currentValue=<synthetic pointer>, newValue=0x1, expectedValue=0x0, this=this@entry=0x20) at ../../src/corelib/thread/qbasicatomic.h:259
#10 fastTryLock (current=<synthetic pointer>, this=this@entry=0x20) at thread/qmutex.h:89
#11 QMutex::lock (this=this@entry=0x20) at thread/qmutex.cpp:225
#12 0x00007faab5fcc9ff in QMutexLocker (m=0x20, this=<synthetic pointer>) at ../../src/corelib/thread/qmutex.h:137
#13 QDBusConnectionManager::busConnection (this=0x0, type=type@entry=QDBusConnection::SessionBus) at qdbusconnection.cpp:127
#14 0x00007faab5fcd95a in QDBusConnection::sessionBus () at qdbusconnection.cpp:1195
#15 0x00007faaa0f6929d in QtCurve::Style::disconnectDBus (this=0x15685f0) at /sda1/home/joaco1.h0m3/rpmbuild/BUILD/qtcurve-1.8.19~git20160811/qt5/style/qtcurve.cpp:701
#16 0x00007faaa0fa59a6 in runAllCleanups () at /sda1/home/joaco1.h0m3/rpmbuild/BUILD/qtcurve-1.8.19~git20160811/qt5/style/qtcurve_plugin.cpp:86
#17 ~StylePlugin (this=0x1549e80, __in_chrg=<optimized out>) at /sda1/home/joaco1.h0m3/rpmbuild/BUILD/qtcurve-1.8.19~git20160811/qt5/style/qtcurve_plugin.cpp:167
#18 QtCurve::StylePlugin::~StylePlugin (this=0x1549e80, __in_chrg=<optimized out>) at /sda1/home/joaco1.h0m3/rpmbuild/BUILD/qtcurve-1.8.19~git20160811/qt5/style/qtcurve_plugin.cpp:170
#19 0x00007faab56613f1 in QLibraryPrivate::unload (this=this@entry=0x1536ae0, flag=flag@entry=QLibraryPrivate::UnloadSys) at plugin/qlibrary.cpp:557
#20 0x00007faab565a6e3 in QFactoryLoaderPrivate::~QFactoryLoaderPrivate (this=0x1549800, __in_chrg=<optimized out>) at plugin/qfactoryloader.cpp:86
#21 0x00007faab565a859 in QFactoryLoaderPrivate::~QFactoryLoaderPrivate (this=0x1549800, __in_chrg=<optimized out>) at plugin/qfactoryloader.cpp:89
#22 0x00007faab569ca66 in cleanup (pointer=<optimized out>) at ../../src/corelib/tools/qscopedpointer.h:60
#23 ~QScopedPointer (this=0x7faab78997d8 <(anonymous namespace)::Q_QGS_loader::innerFunction()::holder+8>, __in_chrg=<optimized out>) at ../../src/corelib/tools/qscopedpointer.h:107
#24 QObject::~QObject (this=<optimized out>, __in_chrg=<optimized out>) at kernel/qobject.cpp:900
#25 0x00007faab5659d52 in QFactoryLoader::~QFactoryLoader (this=0x7faab78997d0 <(anonymous namespace)::Q_QGS_loader::innerFunction()::holder>, __in_chrg=<optimized out>) at plugin/qfactoryloader.cpp:205
#26 0x00007faab7219db9 in (anonymous namespace)::Q_QGS_loader::Holder::~Holder (this=<optimized out>, __in_chrg=<optimized out>) at styles/qstylefactory.cpp:72
#27 0x00007faab7219db9 in operator() (this=<optimized out>) from /usr/lib64/libQt5Widgets.so.5
#28 (anonymous namespace)::Q_QGS_loader::innerFunction()::Holder::~Holder() () at styles/qstylefactory.cpp:158
#29 0x00007faab4d0c139 in __run_exit_handlers (status=0, listp=0x7faab50725a0 <__exit_funcs>, run_list_atexit=run_list_atexit@entry=true) at exit.c:82
#30 0x00007faab4d0c185 in __GI_exit (status=<optimized out>) at exit.c:104
#31 0x00007faab62467f8 in KDBusService::KDBusService (this=<optimized out>, options=..., parent=<optimized out>) at /usr/src/debug/kdbusaddons-5.25.0/src/kdbusservice.cpp:129
#32 0x000000000040cca0 in SystemSettingsApp::SystemSettingsApp (this=0x7ffd1c1a8250, argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/systemsettings-5.7.3/app/SystemSettingsApp.cpp:28
#33 0x000000000040c6ef in main (argc=1, argv=<optimized out>) at /usr/src/debug/systemsettings-5.7.3/app/main.cpp:32