STR: 1. set up first email account ever Expected: Latest emails are shown. Actual: Older emails are shown. Have to scroll up to newest. master + mozilla-central on nexus 4.
Yeah, this is a frustrating one. There's a few things going on here. The lowest hanging fruit for us is to reverse our behaviour on showing the blue new messages bar. We explicitly don't show it for first sync. Instantaneous scroll offset fixes are also an option. Other issues are servers returning envelope results in ascending UID order which will correlate with showing us older messages before new messages. This can be fully addressed by having IMAP be more like ActiveSync or POP and just not showing any results until we have synchronized the entire (most recent) time span, but that pushes out the user seeing anything. This can be best-effort addressed by fetching the UIDs in tranches that move backward. I think there may be a bug on that one. I suggest we just change the blue bar behaviour in this bug and spin off/reference as appropriate for other fixes.
This was addressed by the virtual scrolling implementation only caring about absolute positions indexed by position within the folder. Prior to that the scroll logic cared a lot about visual stability which led to the situation of you being at the bottom of the list when all the other stuff appeared above what you were looking at. The trade-off is visual churn, with higher quality network connections resulting in shorter periods of churn. (Also we have a quick-to-top affordance now.)