Can we talk about this tool?
I use it a lot when drawing, but I feel like this tool has problems most of the time, at least in 3.1.1. I am not going to talk about the fact the tool doesn't work sometimes at all in 3.1.1 for me - I saw there is already a thread about it, but about how sensitive it is.

Currently, the fuzziness can go up to 200, but it seems that any value over 100 just selects the whole canvas, no matter what. I tried drawing a 400px wide pure black (100% opacity) box on a pure white background.
I set the fuzziness to 100, and it only selected the inside of the box, as intended.
I then set the fuzziness to 101, and it selected the entire canvas, and no matter how large the borders of my box are, it'll ignore them and select everything.

of course this was just a test (I don't usually have to such things) but it shows that there could be some small improvements to that tool:

-Reduce the fuzziness amount to 100 max

Make the current value "0" actually be "1" (this way, setting the value to 0 would not make the CAS literally do nothing, and 100 would select everything as it'd actually be the current value "101")
-Reduce the amount increased/reduced when clicking on the arrows next to the fuzziness value from 10 to 5
-Reduce the "sensitivity" of the fuzziness (I currently use the CAS with a fuzziness that go from 1 to 10, never more as it selects well further what I wanted) to make it more subtle and able to select things more precisely.
-Show the parts that are affected more accurately

Sometimes, even though an area appears to be selected by this tool, some areas inside the selection are not fully selected (it is difficult to explain, it is as if they were x% selected, to I have to paint them over several times, like if the opacity was lowered. I think what happens is that if a color is close to the limit of being selected, it gets selected but only partially (example: I'm trying to select red areas, I have a reddish yellow, it'll select it but only "partially" because the color isn't red))

Those would be my suggestions to improve this wonderful tool, that I use a lot in art. I currently find it very impractical because of the fuzziness slider going up to 200 (meaning I have to be very precise with the mouse, or use my keyboard which consumes unnecessary time, to change the value) and having half of that value (from 101 to 200) be apparently useless as it selects all.
And even then, it is way too sensitive to color change and I find it difficult to select subtle color differences (I know if the difference is *too* subtle then it's expected, but I'm talking of fairly noticeable differences in value) - for example if I want to select a shade of red, but not the shade that is next to it and a bit darker, then Krita will just select all the red areas.

Thank you for reading.