Illustrator Resize Rectangle Shape

I have the correct mouse and also the bounding box I can increase the size of the rectangle shape but not decrease it.
That is I am able to increase the height and width of the rectangle shape. I am also able to decrease the width of the rectangle shape but I am not able to decrease the height of the shape.

(After I copy and paste a shape or after I create the shape. While creating the shape I have no problem its only afterward when I want to resize it)