windowck-plugin received signal SIGSEGV, Segmentation fault

Xubuntu 20.04 clean install in a virtual machine. All dependencies installed.

Show the plugin on desktop (show_on_desktop = 1) and Control active windows (only_maximized = 0) should be set.

Thread 1 "panel-1-windowc" received signal SIGSEGV, Segmentation fault.
0x00007ffff7fbd1ee in is_window_on_active_workspace_and_no_other_maximized_windows_above (window=0x555555974220) at windowck-title.c:113

I suspect it has to do with how Xfwm4 stacks windows. At least, that's what I have observed in my debugging process. When the root window (0x0) becomes active for a split second, the plug-in segfaults. The following two files show the correlation between the two events:

The output of a shell script that monitors active window

The output of gdb when PANEL_DEBUG is set

windowck-plugin-1 is added and initialized at 17:20:46.852583081. Opening a new window (of Thunar, in this case) at 17:21:43.964363209 causes the root window to become active and the plug-in crashes at 17:21:44.200072155.

[ 17:21:39.687335343 ]	_NET_ACTIVE_WINDOW(WINDOW): window id # 0x1a00013, 0x0
[ 17:21:43.906980647 ]	_NET_ACTIVE_WINDOW(WINDOW): window id # 0x0, 0x0
[ 17:21:43.964363209 ]	_NET_ACTIVE_WINDOW(WINDOW): window id # 0x1c00007, 0x0
[ 17:21:44.200072155 ]
Thread 1 "panel-1-windowc" received signal SIGSEGV, Segmentation fault.

The gdb log can be fixed with awk 'NR==2 || NR%3==2' tmp.nfA2DicUnK

This issue might be related. See this topic for more details.