What is the merger of Midea and Xiu Xiu? How to merge?

To put it bluntly, the material you are editing is set in the background and you can't modify it.

Right-click to import a material, and then right-click on the material to display "Merge Current Material" and "Merge All". But merging all means merging all the unmerged materials you are editing, and merging the current materials into the one you ordered.