Ah, OK, thanks for posting this. I have seen this before from time to time and as far as I know it is, as you suggest, purely a styling issue that shouldn't cause any breakages to functionality. But I would like to track down the cause of the styling issue if at all possible.
Could you do me a huge favor? If you're willing, what would help me identify the source of this problem most quickly is if you could grant me temporary access to the WordPress admin panel on a website where you have FWP installed and where you are seeing this issue crop up, so that I can inspect it with the web developer tools in my browser. If you're willing to do this, I should be able to figure out the problem and include a fix in the next incremental update. Here's the procedure:
(1) Make sure you've upgraded to the most recent version of FWP (2012.1218, just released today);
(2) Let me know if you still see the problem (I assume that you will);
(3) If so, let me know what web browser (& version of that browser you're using);
and (4) Contact me via e-mail (the Contact form on the plugin website, feedwordpress.radgeek.com , should done fine) to discuss getting the temporary account set up so I can log in and check up on it using the same browser configuration.
Let me know if you'd be willing to help me out with this.