How to reproduce:

1. Create or open any Unity project. (Or downloaded attached one)
2. Add at least 52 animations (ideally more like 100 animations).
3. Open the 'Select Animation' window.
4. Attempt to select an animation at the bottom of the list.
5. Notice that your only option is to scroll through the list slowly, one animation at a time. This workflow is extremely cumbersome and slow for our game animators who work with large lists of game animations all the time.
6. Same issue is with 'Select Properties' in the Transition

Workaround: Press the arrow with the mouse and hold or control with arrow key