How to Edit / Tweak master controllers after creation

After I have created a Master controller grid or Slider is there any way I can then edit the grid later on? ie add more poses to it, or edit / teak the poses in there?

Also,I have noticed slider controllers seem to stop working if I drag the rig from a library into a new scene… not sure what I am doing wrong. Haven’t had the same issue with the grids. I’m on Harmony 21.1 premium

To edit a master controller you have to keep the keyframes it has been created with intact (i mean intact as without unnesessary changes). Then you need to edit those keyframes and create your new M.C.
You can also save a preset of a grid with this button (in Master Controller Grid Wizard window):
and then load and edit it.
I don’t know about this slider problem though.