Silver Dragon is causing an issue with the LFG tool.
When trying to do the world boss Start a Group function. Instead of the usual auto-created one with auto invite, it defaults to the manual raid function.

Is this in wrath or retail? Also, are you using the release or alpha builds of SilverDragon? (There's a major difference right now.)

Sorry for teh delay. Retail and release version v90207.0

Ah. That makes a lot of sense. Just felt weird that it worked once I turned Silver Dragon off. But then, that was after a reloadui which meant the other addon probably did not get a chance to taint.

Oh, that almost certainly means it's a taint issue. Because of how WoW and shared libraries work, the blame for that tends to wind up with whatever the first add-on that happened to load with a given library is, regardless of which user of the library caused the taint.

It's possible that multiple addons could be causing the same issue, if it's taint from dropdown menus -- or the breakage requires that you e.g. open a certain window before it'll affect the LFG tool. I've done a fair amount of work on that in the alpha builds since the last release, so SD itself should soon be less likely to contribute to this.

Okay. Turns out it is not Silver Dragon. Decursive reported the wrong addon. Now I got to figure out what is causing it. Strange as turning off Silver Dragon allowed it to work previously.

Which also means I am going to have a devil of a time finding the culprit. Such joy :D
I'll have to remember to do a /rl before trying to use the LFG. Maybe that will work ;-)