They do have the same number of decimal digits displayed. You can see it by clicking between "float" and "double": the decimal representation stays the same.

What is wrong with that?

It makes it look like they have the same precision (well also, going from 64 to 32 bits zeros out a whole lot, which contributes to that impression). In fact, both decimal representations are usually truncated, and don't accurately represent the binary floating point number. It's a neat and useful tool regardless, and I'm being a bit pedantic.

Click and flip one yes, click and drag many no.