Are there plugins that interfere with the admin part of Rss widget?

I’ve been using the Rss widget in my site, and suddenly a few days ago, the admin part stopped responding.
That is, I’d change the link to the Rss and it wouldn’t get saved (and therefore would show the old Rss in the site). Or I would add another Rss widget, but after I refreshed the admin page, I’d see the widget, but without the links and the other options I added.
Then I got to thinking that maybe one of the plugins could be causing the problem.
Are there known plugins that would do that?