Could you show some FP that has completely replaced the context menu with a new one?
According to the Adobe's documentation, there are two parts that you cannot remove from context menu, they'r Setting section and About section.
You can remove all other parts by using hideBuiltInItems() function.
Like I said, I could not get it working, providing these params should turn RC off completely:
params.wmode = "opaque";
params.menu = "false";
Dont my word for it just ty it yourself.