The ‘Frames' area displays the list and images of each frame added to your animated GIF.
The frames are shown sequentially according to the order they were added and /or later rearranged by moving frames up or down. Frame numbering starts from 0. The selected frame's title bar(s) is/are shown in blue. The rest (unselected) frames' title bars are grey.
Here, you can move selected frames up or down or scroll to the frame you want to select in order to duplicate, delete, move or change its settings.
At the bottom, the total size of the animated GIF and the number of frames are shown.