I would love to Scott but seeing as it only ever shows up in certain instances only I only had other peoples comments that it worked in the first instance
I haven't run any dungeons in about a year I just level toons and do addon stuff now while chatting to the few friends that I have still playing.
All my code ever did was make all those movers children of UIParent and positioned by default in the center of the screen. Everything else was done by nUIs mover code.
All I can think of to test it out is to comment out the 3 bars in your mover code that I have in my plugin and turn off the switch off of my plugin and see if it appears then. Theoretically it will mean that if it appears then the section of code that defines them in the mover system in your code is having problems. If it doesn't appear then the lockFrame function I use to add the frames to the mover system has changed enough to cause a problem.
another option is to change the anchoring system to do the same thing I did and set parent as UIParent and anchor as CENTER and see if that allows it to appear. UIParent is always visible but some frames aren't under certain conditions so could anchoring it to a frame that is intermittently visible causes the new frames to have visibility problems.
Is there a new quest somewhere that uses the new button that will help us test it without running a dungeon? Similar to the Maw of Madness test in Twilight Highlands.