1503388 - Change the modal update preferences error dialog to an inline error

Status: NEW

(Firefox :: Settings UI, enhancement, P5)

Description

[Robin Steuber (they/them) [:bytesized]]

In Bug 1458308, the app.update.auto preference was transitioned, on Windows, to be stored in a file in the update directory. This introduced the possibility of encountering a write error when changing the value of the setting in about:preferences.

Currently, this error is communicated via a native modal dialog box with an error message. Since this error should not occur unless the user messed up the directory structure or permissions, this should be a very uncommon error to see, so the ugly dialog box was considered acceptable. But ideally, we would change this error message to display inline in the page.