These animated GIF's are a User Interface demonstration of context-sensitive overlapping elements. This allows a menu to save space by displaying items only when needed by covering up parts that are not currently needed.
I first saw this concept in the menus of the game, Chrono Trigger. Where it is used in "modal" menus. Making a selection drills-down to reveal more details. Cancelling reverts back to the more general view.
I designed a sprite picker based on this, with two modes. A file selection mode, and a frame-selection mode. Additional animation settings for the current file are revealed by hovering over the "Frozen/Animating" button at the top right.
This concept is useful for any situation where screen-space is limited, or when you don't want to overwhelm the user with more information than they need in that moment. I personally needed a sprite selector like this because I designed my game editor to reserve only a limited amount of screen space for arbitrary editors like these.