Join block won't allow more slots to be added

Bugs and Other Issues
1

I am using the new NEO UI and using the join block.
I use the gear icon to add more arguments/slots to the join block and it lets me.
If I have an empty slot that is not at the end/bottom of the block - I might have an empty slot at position 2. Once I move one of the lower filled in slots up, from position 3 to 2, all empty slots disappear and I am unable to use the gear icon to add more slots to the function.
I have to carefully count out all the arguments I need beforehand and make sure I add them from the top in order or else this happens and I am stuck and have to start over.

2

Thanks for the report Karen. I was able to reproduce this and will see what's going on.

Tracking this as issue 3360:

3

Workaround, click on the mutator and remove the unwanted sockets (drag to left, do not click and delete)
To be on the safe side, remove other blocks from sockets while testing...)