getOptimalPosition() with the limiter restricted by overflowed parents #146

Vertically scroll the container up and down.

Expected:

1. The red square should always remain visible regardless of the position of the scroll.
2. In the initial position, the shapes should represent a small letter "i", with the red dot above.
3. In the opposite scroll position, the shapes should represent an exclamation mark "!" with the red dot underneath.