Thunderbird not syncing gmail folders reliably
I have set up filters in gmail to assign labels to emails and skip the inbox. I have then set up IMAP access in Thunderbird, where these labels translate to folders. New messages do not show up in these folders reliably until I open them in the folder tree.
I have tried ticking "When getting new messages for this account, always check this folder" in the folder properties, which doesn't seem to help at all, and have set mail.check_all_imap_folders_for_new to true, which appears to have made the problem occur less frequently, but hasn't fixed it completely. I estimate that a single-digit percentage of new mail still isn't downloaded until I check manually.
This appears to be the same problem as reported here, but the suggested solution doesn't work for me.