How to create extension block with some pre-defined value?

Hi, im trying to create extension with pre-defined value ( for example string, or int) which would be “sticked” to function in block menu, something like in picture bellow. I have no idea how to write it in Java, or whether it is even possible.

You can see that string is connected to main block in block menu

It’s not possible via extensions. The pre-defined blocks have to be built directly into the sources.

Oh… That’s pitty … but thanks for info :slight_smile: