Someone created a very helpful Add-on for Mozilla Thunderbird Email client named "Quick Folder Move ver 1.2". I use this add-on very much in my use of Thunderbird ver 56.0 for handling emails in my IMAP email account. The Add-on work perfectly for years, but it no longer works in Thunderbird Beta version 58.0b1. I love this add-on so much that I am willing to pay to get it fixed. I cannot move onto using Thunderbird version 58.0 beta until I have this add-on working properly. This add-on worked fine in Thunderbird Beta 56.0, but it quit working in Beta 57.0 and still doesn't work in Beta 58.0
Once this add-on is installed in Thunderbird, you can press Shift+M wile you are on an email, and it will pop-up a list of all your IMAP folder and allow you to pick which folder you want to move the email to. The problem is that the folder list is coming up empty. I'm sure it's an easy thing to fix.
Download Thunderbird Beta here: [url removed, login to view]
Download the Quick-Folder-Move add-on here: [url removed, login to view]
(The file you download is named "[url removed, login to view]", but if you rename it to .zip, you can open it as a normal zip file, and you will have the source code.
Mozilla has a documentation site for developing Thunderbird extensions: [url removed, login to view]
(Everyone please realize this is a free opensource email client, and I paying out-of-pocket for a little-add-on fix. So, there's not a huge budget here. I hope you can understand. I just wanted to throw it out there for some small project person who's wanting to get started. It's not a huge budget in this case.)
I have learned a few things about this by using the Developer Toolbox in Thunderbird (Ctrl+Shift+I).
That got rid of a basic syntax error that kept the tool from even starting.
The more major issue appears to at line 229 in quickmove.js where it iterates over a collection of accounts looking for the root folder. The issue is that as it iterates, it always come up blank, so the folder list does not get populated since method processFolder() never gets called. So, my guess is Mozilla changed something related one of the interfaces this tool uses. So, this is all the time I can spend on it. I have the technical ability to figure this out, just not the time. If you want to dig in, install Thunderbird 58, and the Quick Folder Move add-on and use the Developer Toolbox (Ctrl+Shift+I), and put a break point on line 229 in the Debugger tab on the source file in the left tree under chrome://content/qcuikmove.js