Unwanted "Loop" variables can't be deleted and don't seem to do anything

Software version: 3.8.0.61336
Robot generation: UR5 with CB3

When I add or change a variable assignment in my polyscope program, the drop-down list of variables contains many, many iterations of “Loop_x”, where “x” is an integer. I did not create these variables; they are apparently created automatically when I include a Loop instruction. I do have a lot of loops in my program, but oddly, these variables outnumber the loops that I have. They are annoying, because whenever I assign a variable name, the 50 or so “Loops” that I have to scroll past make it harder to find the variable I actually want.

I also cannot delete these Loop variables. The instruction manual for PolyScope say that I can delete a variable by saving its name as blank spaces, but the program will not allow me to do this with the Loops, or indeed with any variable names.

What purpose are these Loop variables serving, and why can’t I get rid of them?

Thanks,
Anna