How to set shape in small sizes

Hi guys,

Is there some setting to by-passed the minimum limits of a shape sizes ? Beside we manually change the size with mouse.

My case like below : 

Is too small, that I can't give (set) the values inside Width and Height, there is "red line" circle-ing the input box and when I move to another shape/object, it won't save my input. But I do want the shape to be small. I can do it manually by mouse, but it is difficult to have a real nice shape proportion. Like the screenshot, 22 and 27 is not proportional.

Thanks