It happens when the blocked element is toooo long.
In this situations NS should be able to handle the notification properly 'cause it's not possible to close it this way.
There's another thread on this, and I'll try to find it, but you can always view the full message by opening Error Console (Ctrl+Shift+J, or Firefox Tools > Web Developer > Error Console), and click "Messages". You'll find the full ABE message there.
If you can't get rid of the on-screen messages, disable them. NS Options > Notifications, and uncheck "ABE". You'll still get them through the Error Console.ETA:
Here you go: RFE for line-wrap and overlay
I'll put a bump on that and again call it to Giorgio's attention, thanks. (He's been kind of busy lately
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