"Save Configuration" and "Export" don't work when panel has unconfigured launchers

[halogen2]

Environment:

Xubuntu 20.04 live CD

xubuntu@xubuntu:~$ lsb_release -rd
Description: Ubuntu 20.04 LTS
Release: 20.04
xubuntu@xubuntu:~$ apt-cache policy xfce4-panel-profiles
xfce4-panel-profiles:
  Installed: 1.0.10-0ubuntu1
  Candidate: 1.0.10-0ubuntu1
  Version table:
 *** 1.0.10-0ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        100 /var/lib/dpkg/status

Steps to reproduce:

1) right-click the panel > Add New Items, add a launcher. Don't configure the launcher.

2) run xfce4-panel-profiles

3) click either "Save Configuration" or "Export" button

4) try to save

Expected results: configuration should save

Actual results:

At step (4), clicking the "Save" button does nothing. Once this has occurred, clicking "Cancel" doesn't do anything either.

Running xfce4-panel-profiles from Terminal shows this error when this issue occurs -

Traceback (most recent call last):
  File "/usr/share/xfce4-panel-profiles/xfce4-panel-profiles/xfce4-panel-profiles.py", line 217, in on_save_clicked
    self.save_configuration(name)
  File "/usr/share/xfce4-panel-profiles/xfce4-panel-profiles/xfce4-panel-profiles.py", line 205, in save_configuration
    PanelConfig.from_xfconf(self.xfconf).to_file(filename)
  File "/usr/share/xfce4-panel-profiles/xfce4-panel-profiles/panelconfig.py", line 66, in from_xfconf
    pc.find_desktops()
  File "/usr/share/xfce4-panel-profiles/xfce4-panel-profiles/panelconfig.py", line 145, in find_desktops
    for d in self.properties['/plugins/plugin-' + number +
KeyError: '/plugins/plugin-13/items'

Possible workaround:

edit /usr/share/xfce4-panel-profiles/xfce4-panel-profiles/panelconfig.py , change this code at line 144...

                        pv.get_string() == 'launcher':

... to this -

                        pv.get_string() == 'launcher' and \
                        '/plugins/plugin-' + number + '/items' in self.properties:

I can't tell whether Xubuntu 18.04 is affected by this bug or not.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.