No need to become sarcastic. I payed for this App, so please don't treat me as a strayer.
I also payed for this app, and I gave an example where things may be different for different users. Please, excuse my humor.
Its not a question of not showing URLs! Its a question of where the app begins showing the preview. If I put an URL in the textarea, of course it will be shown in any case!
Based on Kostya's explanation of how Aquamail works (quoted below), that's exactly what happened here: Facebook put that URL in the text area. How do you expect Aquamail to decide it was not the intent here, but it is an intent in case of my friends?
Hence my response above.
The preview comes from the text/plain portion of the email message.
In this case it's exactly what was put there by Facebook (or in general, by the sending app).
And what is the long broken line?
I'd suspect those are "equal" symbols that for whatever reason were placed in that message by Facebook. I am guessing they may have wanted to use that either to attract attention to that line or as a separator... You may want to ask FB what they meant.
But it seems, that this problem only occures on facebookmails. Maybe there are only small adjustments needed in Aquamail...
That decision is totally up to the developer.
He might decide to make FB-specific changes in the app's behavior.
To me, that sounds like a slippery slope for a general-purpose e-mail app. (Then someone would ask to tweak it for Yahoo News, another person - for Amazon notifications, ...
And what if FB would change the format of their messages next month?)
I am just expressing my point of view as Aquamail user, while also trying to help others with my favorite app.