[Bug] Setting "Span Monitor" have no effect after changing output

Description: Under Panel Preferences -> Display, there is an option for setting the panel to span across monitors ("Span monitors"). Selecting this option have no effect after changing to non-"Automatic" output, which IS intended behavior. However, after changing the Output back to "Automatic" and re-select "Span monitors", xfce4-panel no longer honors the setting and the panel is ONLY shown on the left-most monitor. To re-emphasize, the issue here is that xfce4-panel does not honor the "Span monitors" setting even when output is set to "Automatic".

Steps to reproduce the bug:

1. Have two monitors setup to extend the display
2. Go to Panel Preferences -> Display, set Output to "Automatic" and set "Span monitors"
3. Check if the panel now extends to both monitors, if it does go to step 4, if not you have already ran into the bug
4. Close the Panel Preference window and re-open it
5. Set output to anything but "Automatic", the "Span monitors" settings should gray-out now
6. Set the output back to "Automatic" and re-select "Span monitors", the panel should now be stuck on the left-most monitor and DOES NOT span across the monitors

Additional information:

~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-panel.xml

<?xml version="1.0" encoding="UTF-8"?>

<channel name="xfce4-panel" version="1.0">
  <property name="configver" type="int" value="2"/>
  <property name="panels" type="array">
    <value type="int" value="1"/>
    <value type="int" value="2"/>
    <property name="dark-mode" type="bool" value="true"/>
    <property name="panel-1" type="empty">
      <property name="position" type="string" value="p=6;x=960;y=14"/>
      <property name="length" type="uint" value="100"/>
      <property name="position-locked" type="bool" value="true"/>
      <property name="icon-size" type="uint" value="16"/>
      <property name="size" type="uint" value="26"/>
      <property name="plugin-ids" type="array">
        <value type="int" value="1"/>
        <value type="int" value="2"/>
        <value type="int" value="3"/>
        <value type="int" value="4"/>
        <value type="int" value="5"/>
        <value type="int" value="6"/>
        <value type="int" value="8"/>
        <value type="int" value="9"/>
        <value type="int" value="11"/>
        <value type="int" value="12"/>
        <value type="int" value="13"/>
        <value type="int" value="14"/>
      </property>
      <property name="span-monitors" type="bool" value="true"/>
      <property name="output-name" type="string" value="Automatic"/>
      <property name="mode" type="uint" value="0"/>
      <property name="disable-struts" type="bool" value="true"/>
      <property name="length-adjust" type="bool" value="true"/>
    </property>
    <property name="panel-2" type="empty">
      <property name="autohide-behavior" type="uint" value="1"/>
      <property name="position" type="string" value="p=10;x=0;y=0"/>
      <property name="position-locked" type="bool" value="true"/>
      <property name="size" type="uint" value="48"/>
      <property name="plugin-ids" type="array">
        <value type="int" value="15"/>
        <value type="int" value="16"/>
        <value type="int" value="17"/>
        <value type="int" value="18"/>
        <value type="int" value="19"/>
        <value type="int" value="20"/>
        <value type="int" value="21"/>
        <value type="int" value="22"/>
      </property>
      <property name="span-monitors" type="bool" value="false"/>
    </property>
  </property>
  <property name="plugins" type="empty">
    <property name="plugin-1" type="string" value="applicationsmenu"/>
    <property name="plugin-2" type="string" value="tasklist">
      <property name="grouping" type="uint" value="1"/>
    </property>
    <property name="plugin-3" type="string" value="separator">
      <property name="expand" type="bool" value="true"/>
      <property name="style" type="uint" value="0"/>
    </property>
    <property name="plugin-4" type="string" value="pager">
      <property name="rows" type="uint" value="1"/>
    </property>
    <property name="plugin-5" type="string" value="separator">
      <property name="style" type="uint" value="0"/>
    </property>
    <property name="plugin-6" type="string" value="systray">
      <property name="square-icons" type="bool" value="true"/>
      <property name="known-legacy-items" type="array">
        <value type="string" value="skypeforlinux"/>
        <value type="string" value="fcitx5 tray window"/>
        <value type="string" value="thunar"/>
        <value type="string" value="variety"/>
        <value type="string" value="networkmanager applet"/>
      </property>
      <property name="known-items" type="array">
        <value type="string" value="dropbox-client-17854"/>
        <value type="string" value="dropbox-client-16725"/>
        <value type="string" value="dropbox-client-4881"/>
        <value type="string" value="dropbox-client-3680"/>
        <value type="string" value="dropbox-client-2369"/>
        <value type="string" value="steam"/>
        <value type="string" value="dropbox-client-2310"/>
        <value type="string" value="Fcitx"/>
        <value type="string" value="dropbox-client-2236"/>
        <value type="string" value="discord1"/>
        <value type="string" value="dropbox-client-7300"/>
        <value type="string" value="Skype1"/>
        <value type="string" value="variety"/>
      </property>
    </property>
    <property name="plugin-8" type="string" value="pulseaudio">
      <property name="enable-keyboard-shortcuts" type="bool" value="true"/>
      <property name="show-notifications" type="bool" value="true"/>
      <property name="mpris-players" type="string" value="chromium.instance1776;chromium.instance1852;firefox.instance129363;firefox.instance1307;firefox.instance1321"/>
    </property>
    <property name="plugin-9" type="string" value="power-manager-plugin"/>
    <property name="plugin-10" type="string" value="notification-plugin"/>
    <property name="plugin-11" type="string" value="separator">
      <property name="style" type="uint" value="0"/>
    </property>
    <property name="plugin-12" type="string" value="clock">
      <property name="mode" type="uint" value="2"/>
    </property>
    <property name="plugin-13" type="string" value="separator">
      <property name="style" type="uint" value="0"/>
    </property>
    <property name="plugin-14" type="string" value="actions"/>
    <property name="plugin-15" type="string" value="showdesktop"/>
    <property name="plugin-16" type="string" value="separator"/>
    <property name="plugin-17" type="string" value="launcher">
      <property name="items" type="array">
        <value type="string" value="16107410501.desktop"/>
      </property>
    </property>
    <property name="plugin-18" type="string" value="launcher">
      <property name="items" type="array">
        <value type="string" value="16107410502.desktop"/>
      </property>
    </property>
    <property name="plugin-19" type="string" value="launcher">
      <property name="items" type="array">
        <value type="string" value="16107410503.desktop"/>
      </property>
    </property>
    <property name="plugin-20" type="string" value="launcher">
      <property name="items" type="array">
        <value type="string" value="16107410504.desktop"/>
      </property>
    </property>
    <property name="plugin-21" type="string" value="separator"/>
    <property name="plugin-22" type="string" value="directorymenu">
      <property name="base-directory" type="string" value="/home/lukas"/>
    </property>
  </property>
</channel>