Preferences blank & Send Later button irresponsive

[Geremia]

Prerequisites

• [X] I am reporting a problem, not asking a question (for questions, go to Discussions).
• [X] I have consulted the user guide.
• [X] I have confirmed that I'm running the current version and the problem persists there (note the version number in fine print next to the add-on name on addons.thunderbird.net and compare it to the version number listed in the add-on details opened from the Add-ons page in Thunderbird; if you've got an old version, click the gear icon and select "Check for Updates").
• [X] If I'm having an issue with date-parsing confusion, I've read the section about that in the user guide and I still think this is something different.
• [X] If I'm having an issue with messages not being delivered, I've followed the troubleshooting steps in the user guide and it's still an issue.

Describe the bug

The preferences are blank:

And clicking the Send Later button doesn't do anything.

File → Send Later does work.

Operating System

Linux

Operating System Version

Slackware64-current

Thunderbird version

128.2.0esr (64-bit)

Send Later start-up string

Nothing appears, even after disabling and re-enabling Send Later. The search box says "2 hidden", but I can't figure out how to make them appear. All the "Errors", "Warnings", etc. buttons are enabled.

[jikamens]

I cannot replicate either of these issues and haven't heard about them from anyone else, so I'm not sure I'm going to be able to help you here, but at the very least I need you to tell me what version of Send Later are using. You can get it by opening the add-ons page and then clicking on Send Later to view its details.

Also would be helpful to send me your error console contents after quitting and restarting Thunderbird and attempting to open the Send Later preferences. After doing those things, type Ctrl-Shift-J in the main TB window to open the error console, Right click on it, select "Save all messages to File", save the file, then email it to send-later-support@extended-thunder.org.

[Lerohi]

I can second this issue, I tried installing multiple different distributions of the addon (Thunderbird-Addons-Release 10.6.0, GitHub-Release 10.6.0 and GitHub-Release 10.6.0_beta) and all of them show the same behaviour for me. The Send Later-buttons in the e-mail-view and the write-view are there, but unresponsive. Further, using CTRL+SHIFT+ENTER to open the Send-Later-menu as well as using File->Send Later lead to the email instantly being moved to the outgoing-folder, which is default thunderbird-behaviour afaik.

I'm too using Thunderbird 128.3.3esr (64-Bit).

Further, I found out that when clicking the Send Later-button in the email-view actually causes the pop-up to open, but at a size of 1px*1px in the bottom left corner of the button (see image above).

On startup, Thunderbird throws the above messages. It seems like the addon (I have only this one installed) is crashing right at startup, probably somewhere inbetween initializing the Send Later-Buttons and defining their on-click-behaviour and a lot of other initializations, which causes the addon to be non-functional. This is just a guess, I would have to look into the source code to verify this.

Also, clicking the Send Later-button (once) causes these errors to appear in the dev console. While not saying much, it tells us that something inside the plugin is crashing (a lot). This is probably due to undefined/uninitialized variables, which would make sense.

Trying to access the addons preferences causes the same error to appear.

[Lerohi]

UPDATE: This bug is NOT related to this plugin, but to Thunderbird in general as it seems.

I conclude that because I was able to reproduce the exact same behaviour with two other plugins. Same error messages, same non-functional-buttons, same missing preferences. Sadly, I haven't yet figured out what is causing this.