Let’s imagine you have a screenful of untagged and tagged images. First, press Alt + T to sort images by tags. With the mouse, click on the left edge of the screen to open the file list. You should see a group of files in the beginning of the list marked as having no tags. Right click on the list to select a whole group of images, and press Ctrl + C to copy the files on the clipboard. Press Ctrl + N to open a new view and paste the images with Ctrl + V. Now you have a nice, clean workspace with no unwanted files.