Reattach the scheduling popup; another attempt to fix Drafts corruption

Reattach scheduling popup for TB128+

The scheduling popup that appears when you type Ctrl-Shift-Enter or Click the "Send Later" button in a compose window is supposed to be "attached" to the button, and things work better overall when it is. Unfortunately, there is/was a bug in Thunderbird 115 which would sometimes make the attached window disappear immediately after appearing, so as a workaround we disconnected the popup from the button [details]. We've been asked by the Thunderbird team whether this is still an issue in Thunderbird 128, so I'm re-attaching the popup to the window for TB128 and newer. However, there is a new preference you can uncheck in the preferences window if you run into problems with this and need to go back to a detached popup.

Another attempt to fix the Drafts folder corruption issue

In rare cases, Thunderbird is corrupting the local copy of the user's Drafts folder when a message is scheduled with Send Later [details]. To be clear, this is a Thunderbird bug, not a Send Later bug, but something Send Later is doing is triggering it. In previous releases I've tried various workarounds, but none of them have worked reliably. This release contains yet aanother attempted workaround approach: monitoring the timestamps on the local Drafts folder data files and not compacting the folder until they have been unmodified for a full second.

Note: Downloading and installing send_later_beta.xpi will subscribe you to future beta releases. We love beta-testers! The advantage is that if there's a bug that affects your workflow you'll help find it and get it fixed quickly. The disadvantage is that bugs are a bit more likely in beta releases. You can unsubscribe from beta releases at any time by downloading and installing send_later.xpi or installing from addons.thunderbird.net.