Hi! I think I may have found a bug in the tools. Sounds like it might be the same as #92045
If you use the frequency analysis on anything, then scroll up to the substitution tool it seems a little broken. Instead of the box with the text and the little boxes with the letter names that you can change it is different.
It still has the long box for the key but underneath instead of the boxes where you can change the letters, it has something like this
Character ^ Frequency
The frequency does match the text you put into the frequency analysis, and the keyword box still works and changes the text but it’s a bit inconvenient to not have the easy labelled boxes for changing the letters. (I end up just opening the frequency analysis in a different tab and using it there instead of within the same tab as the substitution so it still works properly.)
[Thanks for pointing this out, and sorry it has taken a while to get back to you. It definitely needs fixing. I will ask the team to prioritise it. All the best, Harry]