Bug 349023

kdeinit5 crashes if I try to set "special settings for [window|program]" in the window menu

Reproducible: Always

Steps to Reproduce:
1. Click left upper corner/app icon in window title
2. click "weitere Aktionen" (more settings)
3. click special settings

Actual Results:  
Segmentation fault

Expected Results:  
It should not crash

Application: kdeinit5 (kdeinit5), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f2d5ec4c780 (LWP 13852))]

Thread 2 (Thread 0x7f2d486ed700 (LWP 13853)):
#0  0x00007f2d5d01de8d in poll () from /usr/lib/libc.so.6
#1  0x00007f2d5c50e9f2 in ?? () from /usr/lib/libxcb.so.1
#2  0x00007f2d5c51056f in xcb_wait_for_event () from /usr/lib/libxcb.so.1
#3  0x00007f2d499f7089 in ?? () from /usr/lib/qt/plugins/platforms/libqxcb.so
#4  0x00007f2d5d38108e in ?? () from /usr/lib/libQt5Core.so.5
#5  0x00007f2d5b46a354 in start_thread () from /usr/lib/libpthread.so.0
#6  0x00007f2d5d026bfd in clone () from /usr/lib/libc.so.6

Thread 1 (Thread 0x7f2d5ec4c780 (LWP 13852)):
[KCrash Handler]
#5  0x00007f2d5c50f264 in xcb_send_request () from /usr/lib/libxcb.so.1
#6  0x00007f2d5c51496c in xcb_get_property () from /usr/lib/libxcb.so.1
#7  0x00007f2d5e114a50 in NETWinInfo::update(QFlags<NET::Property>, QFlags<NET::Property2>) () from /usr/lib/libKF5WindowSystem.so.5
#8  0x00007f2d4a906921 in ?? () from /usr/lib/libkdeinit5_kwin_rules_dialog.so
#9  0x00007f2d4a8e122f in kdemain () from /usr/lib/libkdeinit5_kwin_rules_dialog.so
#10 0x000000000040b848 in ?? ()
#11 0x000000000040cf9b in ?? ()
#12 0x0000000000404f8c in main ()