User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Firefox/24.0 (Beta/Release) Build ID: 20130910160258 Steps to reproduce: Version 17.0.8 (but this has been happening for a long, long time). I usually delete one or more messages (usually in preview pane). I might delete 1 or a bunch of them at a time. Actual results: The line(s) I am looking at in the preview pane are disrupted, the view changes and the vertical slider on the right side of the window moves up and down (while presumably the software is doing some sort of indexing or sorting). My preview pane view is totally disrupted and I've lost my place of reading in the preview pane. Background info (I've got a bunch (maybe 10 email accounts). About a couple times during the year I move some of the inboxes to some other box to make the system work faster). HOWEVER, what is occurring is so frustrating and it happens multiple times per day). Expected results: (FYI - I spent my career writing and testing software, so I know from which I speak). I have no idea what is happening in the background in order for TB to house-keep the database of email messages, but it should NOT on a regular (multiple times per hour) be doing some kind of visible re-indexing or reordering because I decided to delete 1 or more messages in my in-box. The software should note which message(s) I deleted, remove it from my view in the preview pane and then WAIT for a decent amount of time to when I am NOT actively working in TB to do whatever housekeeping it needs to do. If I close down TB before that time counter triggers a reindex, then it could do the reindexing on either exit or on the next startup. I should not have to sit there, frustrated, multiple times per hour while the entire preview pane changes unexpectedly, and watch the slider on the right move up and down and then leave me at some position in the preview pane (not always the same place) as I was looking at before.

Please fix this. This is so frustrating, that I am thinking of stopping using Thunderbird.

Likely same issue as bug 738249