Dear fellow users of Thunderbird, The title is my issue: After creating a new subfolder, all emails end up there, instead of the inbox or their appropriated folder. Like almost everybody else, I have an email account. All emails are stored on the server of my email provider, and I have my email clients connected to it with IMAP. On my computer I use Thunderbird 78.8.1 to read my emails, and on my phone I use the native email app from LineageOS 17.1. Only my email client on my computer /Thunderbird has filters to sort all my emails in my inbox. Thus I just read my emails on my phone with the native, and read&sort emails on my computer with Thunderbird. All emails stay in my inbox, unless I open Thunderbird to sort&read my emails. With the result that all emails stay in my inbox, unless I open Thunderbird to sort&read my emails to their appropriated (sub)folder. Only the new-new emails are staying in my inbox, and I have to set up and/or change some filters, to have these new-new emails sorted out to their appropriated (sub)folder. But after creating a new subfolder this weekend and set three extra filters to sort some new-new emails to that new subfolder, all new emails go to that subfolder, instead of just these new-new emails. And I have checked it, neither my email client of my provider, nor the native email client of LOS have filters, just Thunderbird. Although all filter settings are what they should be (as I have 15 filters, these are essay to check), all both known-new and new-new emails goes to the newly subfolder. Therefore I think I have found a bug in Thunderbird: After creating a new subfolder, all emails go to that new subfolder, despite all filters are set properly. Iff I only have filters on Thunderbird, and all filters are set properly (I have checked them), then why go all known-new and new-new emails directly to that new subfolder?