I tried to open a file. To do so I moved a directory upwards. I got a lot of .* files, so I tried to deactivate the "show hidden files" option. When I tried to open the options menu of the open dialogue (the one in the right corner) Kate hangs. I am not able to do anything with it. Even closing is not possible.

Reproducible: Always

Steps to Reproduce:
1. got to open file
2. move a folder upwards
3. try to access the settings menu in the upper right corner

Actual Results:  
Kate Hangs

Expected Results:  
the settings menu should be showed

I installed the debug symboles an run kate in gdb. Here you'll find the output.

(gdb) run
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/bin/kate 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
kf5.kiconthemes: "Theme tree: (Breeze)"
kate: Last session is: "scorep"
^C[New Thread 0x7fffd8dd3700 (LWP 28980)]
[New Thread 0x7fffe380b700 (LWP 28975)]

Program received signal SIGINT, Interrupt.
0x00007ffff785a49d in read () at ../sysdeps/unix/syscall-template.S:81
81      ../sysdeps/unix/syscall-template.S: Datei oder Verzeichnis nicht gefunden.
(gdb) bt
#0  0x00007ffff785a49d in read () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007ffff3b4ec89 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007ffff3b61e7b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007ffff3aedfde in QFileDevice::readData(char*, long long) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007ffff3af8815 in QIODevice::read(char*, long long) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007ffff3af9173 in QIODevice::read(long long) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007ffff3af924d in QIODevicePrivate::peek(long long) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007ffff3afa58e in QIODevice::peek(long long) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007ffff3c5740d in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007ffff3c57d84 in QMimeDatabase::mimeTypeForFile(QFileInfo const&, QMimeDatabase::MatchMode) const () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007ffff3c5807f in QMimeDatabase::mimeTypeForFile(QString const&, QMimeDatabase::MatchMode) const () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007ffff3c585a1 in QMimeDatabase::mimeTypeForUrl(QUrl const&) const () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007ffff60e71ed in KFileItem::determineMimeType() const () from /usr/lib/x86_64-linux-gnu/libKF5KIOCore.so.5
#13 0x00007ffff2560210 in KFilePreviewGenerator::Private::resolveMimeType() () from /usr/lib/x86_64-linux-gnu/libKF5KIOFileWidgets.so.5
#14 0x00007ffff3c0973a in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007ffff44e1b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#16 0x00007ffff44e7000 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#17 0x00007ffff3bd7c2b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#18 0x00007ffff3bd9c9b in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007ffff3c30843 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#20 0x00007fffef84dc3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007fffef84df20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007fffef84dfcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007ffff3c30c57 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x00007ffff3bd53e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#25 0x00007ffff46e34b5 in QDialog::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#26 0x00007fffe2befbff in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platformthemes/KDEPlatformTheme.so
#27 0x00007ffff46e336a in QDialog::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#28 0x00007ffff46f5660 in QFileDialog::getOpenFileUrls(QWidget*, QString const&, QUrl const&, QString const&, QString*, QFlags<QFileDialog::Option>, QStringList const&) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#29 0x00007ffff7b7a142 in KateViewManager::slotDocumentOpen (this=0x17) at ../../../kate/src/kateviewmanager.cpp:236
#30 0x00007ffff7ba93d5 in KateViewManager::qt_static_metacall (_o=0x17, _c=24533528, _id=16384, _a=0xffffffffffffffff) at moc_kateviewmanager.cpp:232
#31 0x00007ffff3c089c9 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#32 0x00007ffff44d7722 in QAction::triggered(bool) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#33 0x00007ffff44d9e28 in QAction::activate(QAction::ActionEvent) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#34 0x00007ffff465d18a in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#35 0x00007ffff4662bd4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#36 0x00007ffff466783e in QMenu::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#37 0x00007ffff45251e8 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#38 0x00007ffff4668053 in QMenu::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#39 0x00007ffff44e1b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#40 0x00007ffff44e78eb in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#41 0x00007ffff3bd7c2b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#42 0x00007ffff44e63da in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#43 0x00007ffff453da43 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#44 0x00007ffff453fe33 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#45 0x00007ffff44e1b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#46 0x00007ffff44e7000 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#47 0x00007ffff3bd7c2b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#48 0x00007ffff3f24f82 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#49 0x00007ffff3f26b45 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#50 0x00007ffff3f0b34f in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#51 0x00007fffe5d80590 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#52 0x00007fffef84dc3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#53 0x00007fffef84df20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#54 0x00007fffef84dfcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#55 0x00007ffff3c30c57 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#56 0x00007ffff3bd53e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#57 0x00007ffff3bdd02c in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#58 0x00007ffff7ba63d6 in kdemain (argc=1, argv=0x4000) at ../../../kate/src/main.cpp:439
#59 0x00007ffff7783a40 in __libc_start_main (main=0x400720 <main(int, char**)>, argc=1, argv=0x7fffffffdf58, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffdf48) at libc-start.c:289
#60 0x0000000000400759 in _start ()
(gdb)