I've finally gotten around to updating RSS Ticker. Among other things like new locales and code optimization, this version includes a rewrite of the options dialog and its related code, so any reported bugs related to the Options dialog should be fixed now. This includes the known incompatibility with the All-in-One Sidebar extension.
You can download the latest version of RSS Ticker 1.9 from the RSS Ticker homepage.
On a related note: I originally wrote RSS Ticker so that I could use Firefox's Live Bookmarks to manage my feeds but still have an easy way to see new items from a small number of feeds. Since then, the number of feeds I follow has grown, and the ticker interface has become too restrictive for me. If this sounds like you, you might want to check out my new extension called Feedbar. It uses your Live Bookmarks for feed management like RSS Ticker, but it displays the new items in a sidebar, so it's easier to scan through a large number of feeds.