User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

Using Beta 114.0b5 (64-bit) I have two email accounts using the unified inbox.

Actual results:

Using the Unified Inbox I find that the message list is blank for at least 15 seconds when first loading.

Expected results:

It should populate immediately, as it does in the stable version

I can confirm that this is indeed the case, not only for the Unified Inbox, but all the other Unified folders as well. Perhaps the title of this bug needs to be reworded to reflect that and the following observations I've made:

When switching from one Unified folder (e.g. Inbox) to another Unified folder (e.g. Sent), the Threads Pane (message list) goes blank as Thunderbird searches each IMAP folder.

The message list gets populated with messages as soon as Thunderbird finishes searching all IMAP folders.

As a result, you cannot access old messages that had already been fetched the previous times Thunderbird had checked the accounts, until it's finished searching the IMAP folders. The more folders there are in the Unified folder's search scope, the longer it takes Thunderbird to search all of them and the longer you have to wait for the message list to populate. On a slow internet connection, the experience is even worse, even with a few folders involved in the online search.

This delayed population of the message list doesn't happen when Thunderbird is taken offline via File -> Work Offline.

Duplicate of any other perf issues? https://mzl.la/3qsmEqO

Does your Inbox have thread view enabled?

(In reply to [:Aureliano Buendía] from comment #3)

Does your Inbox have thread view enabled?

Yes, I am using threaded view.