src/vs/editor/common/cursor/cursorCollection.ts/CursorCollection/_removeSecondaryCursor
class CursorCollection:	private _removeSecondaryCursor(removeIndex: number): void {
		if (this.lastAddedCursorIndex >= removeIndex + 1) {
			this.lastAddedCursorIndex--;
		}
		this.cursors[removeIndex + 1].dispose(this.context);
		this.cursors.splice(removeIndex + 1, 1);
	}