Problem with crop tool and eraser tool on bitmaps

Hi all. I have been using X7 for a number of years and suddenly when I use the crop tool and eraser tool on bitmaps in Coreldraw its not 'visually' working. I can see the nodes have gone but can still visually see the full original image. Tried on various images - same problem. I have also exported the image as a JPEG and the full image is still there, My PC has been recently been reformatted and I also tried out the trial version of Corel 2021 which I have now uninstalled. Not sure if either of those two factors would by chance have had an impact? Anyone have any idea how to fix this, been going around in circles? Thank-you