Map zooming confusion

In FFXIV, when I resize the map window to the minimum, why can’t the full map scale to fill the window properly?

That means I always have to drag the map when the window has to been scaled to minimum. I don't play with controller so I'm not sure if this is comfortable by controller or not.

This has been bothering me for years and I'm not sure if anyone has ever discussed it before. Or is this widely accepted by the player base?

The scroll wheel can zoom in and out to solve that.