First issue was the following:
The original panel (Panel 1) I edited was the stock panel. I plugged in another monitor (Monitor B) and that panel went to Monitor B. I tried using Display Configuration to change the settings to make the Monitor A the primary monitor, but that did not put Panel 1 back to Monitor A. I tried moving Panel 1 to Monitor A, but when moving from Monitor B to Monitor A, the panel disappeared. I created a new standard panel in Monitor A (Panel 2).

Yesterday, I turn my computer on with both monitors on and found Panel 1 on Monitor B. I tried manually moving it to Monitor A and it worked.

Today, I deleted Panel 2 (after making the same modifications to Panel 1, that I started making to this panel) and in doing so, DrKonqi showed up because plasmashell crashed. The desktop wallpaper also reverted to default. Here's the backtrace:

Application: Plasma (plasmashell), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f74a50bf800 (LWP 818))]

Thread 10 (Thread 0x7f748dfac700 (LWP 820)):
#0  0x00007f749e54d18d in poll () from /usr/lib/libc.so.6
#1  0x00007f74a3597ae2 in ?? () from /usr/lib/libxcb.so.1
#2  0x00007f74a3599757 in xcb_wait_for_event () from /usr/lib/libxcb.so.1
#3  0x00007f748f6deca9 in ?? () from /usr/lib/libQt5XcbQpa.so.5
#4  0x00007f749ec57a9e in ?? () from /usr/lib/libQt5Core.so.5
#5  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#6  0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 9 (Thread 0x7f74871c4700 (LWP 883)):
#0  0x00007f749a9ae163 in g_main_context_prepare () from /usr/lib/libglib-2.0.so.0
#1  0x00007f749a9aeba8 in ?? () from /usr/lib/libglib-2.0.so.0
#2  0x00007f749a9aed8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#3  0x00007f749ee8f25b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#4  0x00007f749ee3626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#5  0x00007f749ec52af4 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#6  0x00007f74a1ffd335 in ?? () from /usr/lib/libQt5Qml.so.5
#7  0x00007f749ec57a9e in ?? () from /usr/lib/libQt5Core.so.5
#8  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#9  0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 8 (Thread 0x7f747c7f4700 (LWP 907)):
#0  0x00007f749dd5207f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
#1  0x00007f747f9e904a in ?? () from /usr/lib/xorg/modules/dri/radeonsi_dri.so
#2  0x00007f747f9e8787 in ?? () from /usr/lib/xorg/modules/dri/radeonsi_dri.so
#3  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#4  0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 7 (Thread 0x7f74768fc700 (LWP 910)):
#0  0x00007f749a9f3414 in g_mutex_unlock () from /usr/lib/libglib-2.0.so.0
#1  0x00007f749a9ae1b0 in g_main_context_prepare () from /usr/lib/libglib-2.0.so.0
#2  0x00007f749a9aeba8 in ?? () from /usr/lib/libglib-2.0.so.0
#3  0x00007f749a9aed8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#4  0x00007f749ee8f25b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#5  0x00007f749ee3626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#6  0x00007f749ec52af4 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#7  0x00007f74a1ffd335 in ?? () from /usr/lib/libQt5Qml.so.5
#8  0x00007f749ec57a9e in ?? () from /usr/lib/libQt5Core.so.5
#9  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#10 0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 6 (Thread 0x7f7474e84700 (LWP 913)):
#0  0x00007f749e54d18d in poll () from /usr/lib/libc.so.6
#1  0x00007f749a9aec7c in ?? () from /usr/lib/libglib-2.0.so.0
#2  0x00007f749a9aed8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#3  0x00007f749ee8f25b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#4  0x00007f749ee3626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#5  0x00007f749ec52af4 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#6  0x00007f74a1ffd335 in ?? () from /usr/lib/libQt5Qml.so.5
#7  0x00007f749ec57a9e in ?? () from /usr/lib/libQt5Core.so.5
#8  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#9  0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 5 (Thread 0x7f746f3d4700 (LWP 929)):
#0  0x00007f749dd5207f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
#1  0x00007f74a484c564 in ?? () from /usr/lib/libQt5Script.so.5
#2  0x00007f74a484c5a9 in ?? () from /usr/lib/libQt5Script.so.5
#3  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#4  0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 4 (Thread 0x7f746c8f4700 (LWP 971)):
#0  0x00007f749a9f33f9 in g_mutex_lock () from /usr/lib/libglib-2.0.so.0
#1  0x00007f749a9ae1c9 in g_main_context_prepare () from /usr/lib/libglib-2.0.so.0
#2  0x00007f749a9aeba8 in ?? () from /usr/lib/libglib-2.0.so.0
#3  0x00007f749a9aed8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#4  0x00007f749ee8f25b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#5  0x00007f749ee3626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#6  0x00007f749ec52af4 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#7  0x00007f74a2bc51f6 in ?? () from /usr/lib/libQt5Quick.so.5
#8  0x00007f749ec57a9e in ?? () from /usr/lib/libQt5Core.so.5
#9  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#10 0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 3 (Thread 0x7f73d78dc700 (LWP 1148)):
#0  0x00007f749a9f33f5 in g_mutex_lock () from /usr/lib/libglib-2.0.so.0
#1  0x00007f749a9aeb7d in ?? () from /usr/lib/libglib-2.0.so.0
#2  0x00007f749a9aed8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#3  0x00007f749ee8f25b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#4  0x00007f749ee3626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#5  0x00007f749ec52af4 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#6  0x00007f73d9e37a57 in KCupsConnection::run() () from /usr/lib/libkcupslib.so
#7  0x00007f749ec57a9e in ?? () from /usr/lib/libQt5Core.so.5
#8  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#9  0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 2 (Thread 0x7f73cb5e4700 (LWP 1228)):
#0  0x00007f749ee8e7df in ?? () from /usr/lib/libQt5Core.so.5
#1  0x00007f749a9ae1bd in g_main_context_prepare () from /usr/lib/libglib-2.0.so.0
#2  0x00007f749a9aeba8 in ?? () from /usr/lib/libglib-2.0.so.0
#3  0x00007f749a9aed8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#4  0x00007f749ee8f25b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#5  0x00007f749ee3626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#6  0x00007f749ec52af4 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#7  0x00007f74a1ffd335 in ?? () from /usr/lib/libQt5Qml.so.5
#8  0x00007f749ec57a9e in ?? () from /usr/lib/libQt5Core.so.5
#9  0x00007f749dd4c4a4 in start_thread () from /usr/lib/libpthread.so.0
#10 0x00007f749e55613d in clone () from /usr/lib/libc.so.6

Thread 1 (Thread 0x7f74a50bf800 (LWP 818)):
[KCrash Handler]
#5  0x00000000036b7890 in ?? ()
#6  0x00007f749ee6d9c0 in QObject::connect(QObject const*, char const*, QObject const*, char const*, Qt::ConnectionType) () from /usr/lib/libQt5Core.so.5
#7  0x00007f74a1f3856a in ?? () from /usr/lib/libQt5Qml.so.5
#8  0x00007f74a1f38758 in QV4::QObjectWrapper::wrap(QV4::ExecutionEngine*, QObject*) () from /usr/lib/libQt5Qml.so.5
#9  0x00007f74a1ebceac in QV4::ExecutionEngine::fromVariant(QVariant const&) () from /usr/lib/libQt5Qml.so.5
#10 0x00007f74a1fed259 in QV4::QmlContextWrapper::get(QV4::Managed*, QV4::String*, bool*) () from /usr/lib/libQt5Qml.so.5
#11 0x00007f74a1ec47c3 in QV4::ExecutionContext::getProperty(QV4::String*) () from /usr/lib/libQt5Qml.so.5
#12 0x00007f74a1f4fc17 in QV4::Runtime::getActivationProperty(QV4::ExecutionEngine*, int) () from /usr/lib/libQt5Qml.so.5
#13 0x00007f749eb9a7cd in ?? ()
#14 0x0000000200000001 in ?? ()
#15 0x02d9e8d700000000 in ?? ()
#16 0x0000000000000001 in ?? ()
#17 0x0000000002076460 in ?? ()
#18 0x000000000354aba0 in ?? ()
#19 0x00007f74a2c56828 in QQuickItemPrivate::paintOrderChildItems() const () from /usr/lib/libQt5Quick.so.5
#20 0x02d9e8d7e7973000 in ?? ()
#21 0x00007f74a233e300 in ?? () from /usr/lib/libQt5Qml.so.5
#22 0x00007f746f801008 in ?? ()
#23 0x0000000001efad70 in ?? ()
#24 0x00007f7474654030 in ?? ()
#25 0x00007f7474644180 in ?? ()
#26 0x0000000000000000 in ?? ()


Reproducible: Didn't try



Expected Results:  
Originally, Panel 1 should have not crashed. Also, Display Configuration should actually work when selecting the primary monitor, but I'm not sure that you guys handle that, could be a different development team.

I'm using Manjaro 15. 09 Bellatrix (64bit) with the Linux 4.1.10-1 kernel and Qt 5.5