Showing more than 15 recent folders in move-to and copy-to context menus is easy in Thunderbird 91.

I’m a heavy user of many IMAP folders for organizing email (and Günter Gersdorf’s brilliant Thunderbird extension Copy Sent to Current), moving emails to folders quickly is important.

Thunderbird long has remembered which folders were used most recently, offering to move or copy mails there in a separate menu, but the default number of folders shown there was a miserly 15 folders. Previously, increasing that number required a rather hidden hack, but in the latest version of Thunderbird (91 at the time of writing), it is easy:

Simply open the “Config Editor” in the preferences, and change the key mail.folder_widget.max_recent to your preferred value; 40 for me.