Extension icon pinned to toolbar is invisible

[raleik-pl]

Description

I've installed an extension (Checker Plus for Google Calendar™ by Jason Savard). It installas fine, and it works fine. But the extension icon is only accessible in the Extensions dropdown menu

After I rightclick the extension and choose "Pin to Toolbar", the icon disappears from the dropdown but is not added to toolbar - it disapears completely.

The only way to get it back is to "Restore Defaults" in "Customize Toolbar" editor.

Steps to Reproduce

• Install "Checker Plus for Google Calendar™ by Jason Savard"
• See the extension is available in "Extensions" dropdown
• Rightclick the extension and "Pin to Toolbar"
• Notice the extension is gone, there is no icon on the toolbar nor in the dropdown.

Additional Information

n/a

Affected Websites

This also happened with some other extensions, e.g. "Simple Translate" by sienori

Environment

Firefox 131.0.3 64bit
firefoxpwa 2.15.5

[filips123]

Please check if this happens if you install a new web app into a fresh web app profile.