Some information about gimpfu3.
It was actually a coincidence: I was looking for an answer as to why the older plugins did not support the colors of the chosen theme.
Fallow-Path by arakne from 2014 was also such a plugin.
I looked at the code with interest and found it very easy to adapt gimpfu3 to other plugins (and doesn't require knowledge of gtk).
I act like this:
1. On site
'from gimpfu import *' paste gimpfu3 code (to avoid Windows problems with multipart plugs, but also for the user's convenience when installing the plugin),
2. I only modify the data contained in the register () according to simple rules and supplement def (.....) with added parameters.
This way, there is no conflict between the original gimpfu.py and gimpfu3, and I don't interfere with the plugin's runtime (whose logic sometimes I don't understand yet).
It's really simple and fast (just a few new PF_XYZ rules) and I still don't understand why these great solutions haven't been followed by other plugin authors.
I changed your plug in less than an hour and it works fine.
Just because only the author knows everything about his plugin, take your time to answer - you will learn the rules, change this plugin and a few others from your extensive collection.
Ideally, you should also add a preview, but fu_preview has a few additional limitations.