Finding bucket Fill Threshold slider

[jimav]

Hi, Inexperienced Gimp user here.    Where exactly is the Bucket "Fill Threshold" slider?  I see it in the Bucket Fill tool options in some Youtube videos but don't see it in the similar options screen in my system. 

A screenshot of what I see is attached as "gimp_no_FT.png"

A screen capture of a youtube video showing it is "youbube.png" (sorry, fuzzy).

What am I missing/confused about?

Thanks for any help.
-Jim

Gimp 2.10.36 on Ubuntu 24.04

[PixLab]

You need to Activate/Select Fill similar colors or Fill by line art detection, because Fill whole selection (which you are actually on) does not have those options.
Once one of those two option selected the sub-menu will appear below