SemanticDiff provides a minimap to give you an overview of all the changes in a file. It is located next to the scrollbar and covers all expanded areas. When you load or hide context, the minimap is updated. It shows all removed code in red on its left side and all added code in green on its right side.
Other colors are used to highlight moved code blocks. Instead of using red and green, moves use the color assigned to them on both sides. This makes it easy to see directly in the minimap how much code has been moved and where the source and target are located. The color is the same as the one used as a border around the source and target inside the diff: