Show button to index messages beyond the initial 1000 about runbox7

[castaway]

@gtandersen I don't understand this one, could you add some screenshots?

[gtandersen]

Couldn't reproduce this now with a brand new account; there is only the initial popup prompting to synchronize the index.

However when that prompt is affirmed, no indication is given that synchronization is active -- and the button in the lower left corner still says "Synchronize index".

Perhaps what is needed here is to start index synchronization and not stop at 1000 messages?

[castaway]

With a brand new account presumably it doesnt contain 1000+ messages? ;)

[gtandersen]

@castaway New users migrating from other services regularly import much more than 1000 messages, and if they don't receive much new incoming email their account could be left without a server index as well (and we routinely initiate indexing for new accounts manually).

[gtandersen]

Created #1485 for the issue where no index is created mentioned in #1454 (comment).