I just upgraded from Photoshop CC 2019 to Photoshop 2021, and I found a bug. When you hit Command-Option-0, the image should zoom to 100% and resize the window so the entire image is visible (unless the image is so large that it can't be contained on the monitor), regardless of the current magnification. If your image is zoomed to 100% but 1) the window is larger than the image so that the Artboard shows, or 2) the window is smaller than the image so that scrollbars are present, Photoshop does nothing. In the example below, all three situations should result in the same thing; instead, only the bottom situation works properly. Please fix this.