Rated 5 out of 5 stars

per dreadnaut el jun. 3, 2008 · enllaç permanent

BorderColors is a very light extension that adds a configurable border to any compose window, colour-coded to remind you what will appear in the From: field.

Configuration is trivial, one just has to assign colours to each email account; after this, the extension is failry unobtrusive but effective: the thin border is a bright alert, in case you are using the wrong account.

Extension has been working fine for months now, I'm surprised is still in the sandbox.