Step 1: 1) Locate the Dialog's special menu
Step 2: Add a second "layers" Dialog
Step 4: Switching to manual image selection.
Note: choosing the image here does not change which image is active. It merely changes which image's layer is shown in the dialog. The active image is the image whose window was last activated using window management.
Tip: You can use scrollwheel on the image selector to choose between images in the 2nd "Layers" dialog.