Custom Icon from file not working anymore (input field does not appear)

[capi1O]

Steps to reproduce

• Open Firefox in a new profile
• Install Sidebery
• Right click on the default Tabs panel and select "Configure Panel"
• In "Custom Icon" section select "File"

Actual behavior

Nothing appears to select a file, see screenshot:

Expected behavior

The input field should appear below allowing us to select a file.

System

Windows 11 & Arch Linux (tested both)

Firefox version

134.0.1 on Windows and 133.0.3 on Linux

Sidebery version

5.3.2

Logs

Nothing in the logs

Possible cause

I believe the issue comes from commit 8a7eda8 which places panel config in a pop-up however I did not check it.

[Gadget64]

It does not seem to work in the regular settings page either for me, not just in the pop-up (running Sidebery 5.3.2 too, Firefox 135.0 on macOS 15.3). Downgrading the extension one version at a time showed that the file picker was working back in 5.2.0, but has been broken since 5.3.1 at least (I could not find 5.3.0 on AMO), if this potentially helps; though this certainly does not exclude that it does come from 8a7eda8, as that seems to have changed the most about the file picker inbetween – from my outside perspective at least.