Unity 5 UI Keeping rounded corners same proportions.

Hey everyone, I’m trying to find a way to keep rounded corners the same proportions for my button. The only answers I see are for the old gui system.

Thanks for helping! Here’s a picture to help.
51122-2015-07-27-17-50-46.png

Don’t change the scale of the button but the width of the RectTransform component.

Moreover, don’t forget to set the Image type (on the Image component) to Sliced.