New
#71
I've had a temporary solution to my problem. I used a portable version of the latest Pale Moon x64. This required a fresh install of my add-on's and their settings into the portable folder.
As I understand it, Firefox has the old engine and the ionMonkey engine working side-by-side. There are also UserInterface changes. Add-on's in the profile may pass certain criteria but still interfere and struggle with the changes. That's my perspective for now, until I do more experimenting and transitioning into the non-portable version.