In the Find & Replace dialog you cannot use the mouse to move to the second panel. It requires a Tab key.
That is reaaaaally weird, but yup, it does that for me also. I’m really curious how this could have happened, I wouldn’t know how to make that happen on purpose!
Strange. I can move between windows with either tab or mouse click…
Is this maybe an operating system issue again (my Big Sur does other strange things but not this)
I don’t know why it is working for you because there was definitely a bug, which I fixed a few weeks ago. The fixed version has not been released yet however. The problem had nothing to do with the macOS version.