User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.0.04506; .NET CLR 1.1.4322) Build Identifier: version 2.0.0.0 (20070326) When you have a folder with many mails (200 / 300) and you want move some of them to a new one, if you do this as sum of two operations (1 selecting a set and moving them; 2 selecting a second set and moving them) in the destination folder mails are lost. I think that the background index creation with the second move operation is stopped. Looking with explorer into application data foldere where Thunderbird stores mails, initially the data file is big, but if you compact the folder, it is reduced. Reproducible: Always Steps to Reproduce: 1. Create a new folder (or subfolder) 2. Select in a folder with many mails some of them and move into previous new folder 3. Without displaying the list content of the destination folder, in the source folder select some other mails and move them also. 4. Now in the destination folder you can't see the sum of the two operation, but less mail. Tipically you loss mail of first operation. Actual Results: Mails loss. Expected Results: Preserve all my mails!

The move operation is made whit drag and drop and not by context menu move to...