Action bar bug.
 

The button to fire the cannons before and during the Galakras encounter in SoO is missing from my UI while using nUI. Is there a fix for this?

Was it there in 5.3 ? Last nUI version ? Which version of nUI are you using ?

What is SoO ? I haven't raided in this expansion much if at all so don't know all the raids.

Ah, siege of origomar or however its spelt. I watched a video of this but couldn't see the cannons in use to see what sort of bar it is. But I suspect, if it isn't working in the new one that it is the same one that is being used in the new cooking quest as that isn't working either. And seeing as I can't very well debug a raid situation rofl .. if I even run it with the guildies at some point .. I just hope there is a simple quest out there that doesn't involve dungeons or raids to get to so that I can test and hopefully fix it but otherwise ... it might be hard to track down unless someone else has located the problem in something like bartender or dominoes and have fixed it.

I have an update on this issue. It appears that while entering the cannons, the button to shoot briefly appears on the stance bar (I'm a rogue, so I see it appear next to Stealth/Shadow Dance), then immediately disappears again. I am not sure if this helps or not, but I'd like to help fix this issue if possible because I really like the UI and have been using it for several years now.

I think I read on the forums here some simple quest scenarios that now use a special macro conditional so will see if I can get the same effect you do on that quest which will hopefully mean a solution to that will be a solution to your problem.