I'm Very happy with Krita 4.1.1. Runs smoothly with low resource consumption as it should. Finally I can drop version 3.1.1. My very first impression about the reference tool was: where is the masking tool? Or... A way to cut the picture temporally to a smaller size. Example. I load a human figure as reference, but need just a detail of the whole, let's say the head. So I adjust the boundaries of the reference image to show just the head, meanwhile the reference picture beneth rests unmodified and in the same scale ratio.
*** This bug has been marked as a duplicate of bug 399061 ***