glade 3.22.2 crashes when add toplevel

[Alan Campbell]

ran

export GDK_SYNCHRONIZE=1
glade

on command line

immediate output:

GladeUI-Message: 10:19:36.816: 1 missing displayable value for GtkWidget::events
GladeUI-Message: 10:19:36.817: 3 missing displayable value for GtkWidget::AtkObject::accessible-role
GladeUI-Message: 10:19:36.894: 1 missing displayable value for GtkEntry::input-purpose
GladeUI-Message: 10:19:36.894: 2 missing displayable value for GtkEntry::input-hints
GladeUI-Message: 10:19:37.018: No displayable values for property GtkMenu::anchor-hints
GladeUI-Message: 10:19:37.066: 5 missing displayable value for GtkAboutDialog::license-type
GladeUI-Message: 10:19:37.173: 1 missing displayable value for GtkCellRendererAccel::accel-mode
GladeUI-Message: 10:19:37.239: No displayable values for property WebKitWebView::automation-presentation-type
GladeUI-Message: 10:19:37.246: No displayable values for property WebKitSettings::hardware-acceleration-policy
GladeUI-Message: 10:19:37.246: Glade needs artwork; a default icon will be used for the following classes:
 GThemedIcon needs an icon named 'widget-gtk-themedicon'
 GtkApplicationWindow needs an icon named 'widget-gtk-applicationwindow'
 WebKitSettings needs an icon named 'widget-webkit2gtk-settings'
 WebKitWebView needs an icon named 'widget-webkit2gtk-webview'

none of which is a problem

glade opens

created new project

when I select any item in top level menu, glade crashes

output:

(glade:18775): Gdk-WARNING **: 10:19:42.484: ../../../../../gdk/x11/gdkwindow-x11.c:5633 drawable is not a native X11 window

(glade:18775): Gdk-ERROR **: 10:19:42.485: The program 'glade' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 124818 error_code 3 request_code 20 (core protocol) minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the GDK_SYNCHRONIZE environment
   variable to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
Trace/breakpoint trap (core dumped)

journalctl | grep glade says

dbus-daemon[927]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service' requested by ':1.301' (uid=1000 pid=19074 comm="glade " label="unconfined")

kernel: traps: glade[19074] trap int3 ip:7fd8f004f0d5 sp:7ffefb906770 error:0 in libglib-2.0.so.0.6400.3[7fd8f0013000+84000]

==========

selecting items from e.g. Display menu (e.g. GtkImage), then right clicking in project list and "Add widget as top level" wroks as expected

==========

running

glade <path to existing ui file created in generated with glade 3.22.1>

has same result

==========

On ubuntu Ubuntu 20.04.1 LTS, clean install but many packages already installed

linux 5.4.0-62-generic

glade package 3.22.2-1

[Alan Campbell (entropyreduction)]

I uninstalled glade package 3.22.2-1 and installed 3.22.1-1 from

https://packages.ubuntu.com/bionic/amd64/glade

which ran but exactly the same crash, as described above.

[Alan Campbell (entropyreduction)]

Since no one else is reporting this problem, it's probably something I'm doing wrong. Any suggestions about how to fix?