"Add preface to the browser window's title if Sidebery sidebar is active" appends empty value for %PN after a Firefox restart until the panel is switched once

[KernelLeak]

Steps to reproduce

• Turn on "Add preface to the browser window's title if Sidebery sidebar is active"
• Set "Preface value" to "[%PN] "
• See window title correctly prefixed with "[Tabs] " (might be something else, e.g. I named my Tabs Panel "Tabs")
• Restart Firefox

Actual behavior

• See window title prefixed with "[] "
• Disabling/Enabling the sidebar removes and adds back the wrong "[] " prefix
• Switching to a different panel in Sidebery (like "🌐" - I'm using Emoji as short Panel titles) gets the correct "[🌐] " title prefix back for this window until the next Firefox restart

Expected behavior, possible causes and additional notes

Until I updated from 5.4 to 5.5.0.1 this worked correctly immediately upon restarting Firefox - I use a different panel per window to differentiate between the 6 windows I have open all the time...

System

Windows 10

Firefox version

Firefox 149.0b2

Sidebery version

5.5.0.1

Logs

[KernelLeak]

For what it's worth - hitting the "reload" button in the extension log/debug tab to reload Sidebery also makes all prefixes revert to being "[] ".

Toggling the "Add preface to the browser window's title if Sidebery sidebar is active" option afterward makes the prefixes show correctly again.