Hi,
While Similarity was working, I tried to delete some duplicate files as they were completely similar (good work !).
So, i selected the file I wanted to delete, then I tried to delete it but just at this moment, focus line moved to the previous line because a new duplicate file has been inserted before. Thus, I deleted another file (fortunately, I recover it in trash).
I suggest that focus line does not change when new duplicate files are detected.
thx for your great job,