Thunderbird's New Version 128 is significantly slower for some functions

[treedude]

 Thunderbird's New Version 128 is significantly slower for some functions. Soon after it installed I read the release notes stating that, due to updated coding, Thunderbird is "faster". Then I noticed it immediately:

1. Upon startup, the opening of the Inbox (100-200 msgs) takes some time. I see this "No Message Found" message displayed for a few seconds before the Inbox loads.

2. Opening a folder in a new tab takes more time; I see this:

     - "No Message Found" displays for a second or more before the folder loads.

     -  How long the "No Message Found" displays appears to be dependent on how many messages are in the folder.

     - Previously the folder would start loading immediately.

3. Running Filters takes (guessing) 2-3x longer now. I have a couple hundred filters that I run manually on incoming mail and it takes up to a minute or more to complete.

    - How long it takes seems to depend on how many messages are being filtered.

    - Previously, it would take no more than (guessing) 20-seconds max.

4. Deleting messages takes longer before it starts deleting:

    - Previously it would start deleting immediately, but, now it appears to "pause" for 30-seconds before it starts deleting messages (at the same rate as before).

    - I just did a test: Deleted 350 messages and the "pause" was about 30-seconds before it started deleting messages. When I hit "UNDO" and repeated Delete of the same 350 messages, there was no pause before it started deleting. I'm guessing the "pause" was loading the messages into memory; they were already in memory the 2nd time.

Treedude

[Sajit]

I and many others are seeing the same problem.

When will this be resolved ? Can someone from the Thunderbird team provide an immediate status update ? 

[mfx]

Same here.

Previously being really fast and responsive, Thunderbird now stalls and freezes all the time. The most significant symptom is that "no message found" when switching to the inbox.

[rsbrux]

My problem is with deleting messages. After upgrading from 115 to 128, the performance became abysmal.  I was able to improve it slightly by disabling indexing, but the GUI would still hang for over a minute when I deleted a message.  This was independent of the mail account I was deleting from. Now it sometimes hangs for over 3 minutes when I delete a message.  My biggest folder is about 1.2GB with less than 10k messages.  I am using 128.5.2esr-bb19 (64-bit) flatpak.

[rsbrux]

P.S. Today it took almost 10 minutes to regain UI response after deleting *one* message!