I've been using Thunderbird for more than 15 years, and have an extensive folder structure (easily more than 300 folders). Dragging and dropping emails for filing them is not realistic. It would be great to have keyboard shortcuts for moving & copying emails, and for being able to "jump" from one folder to another. There currently is an add-on (Quick Folder Move) that does this, and I'm grateful for it (and I've contributed funds to the developer for it). That being said, I don't think I can expect a developer to maintain their add-on in perpetuity in order to stay current with each release of Thunderbird. It would therefore be great if that capability was part of Thunderbird itself.
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