void DrawSelection()
{
for (int r = 0; r < Height; r++)
{
int item_idx = top_item + r;
bool selected = (item_idx == selected_item);
Console.ForegroundColor = selected ? ConsoleColor.Black : ConsoleColor.Gray;
Console.BackgroundColor = selected ? ConsoleColor.Cyan : ConsoleColor.Blue;
var item = Prefix + Completions[item_idx];
if (item.Length > Width)
item = item.Substring(0, Width);
Console.CursorLeft = Col;
Console.CursorTop = Row + r;
Console.Write(item);
for (int space = item.Length; space <= Width; space++)
Console.Write(" ");
}
}