I spent several hours rating over 3000 images for eventual export, and lost all this work by accidentally pressing Ctrl-A before pressing Ctrl-3 to rate an image. I didn't see that all images were selected, because I was in preview mode, where only one image was decorated with a blue border, even after Ctrl-A selected all images. It seems like a separate bug that there is no visual indication in preview mode which images are selected. It is quite annoying that it is so easy to lose a lot of work. I think there should be a way to undo an action like this. Maybe also Ctrl-A should be disabled in preview mode. Reproducible: Always
*** This bug has been marked as a duplicate of bug 142753 ***