How do I use 9-patch

I don't understand how 9-patch works on construct. I'm using construct 3.

1/. I create a new 9-patch.

2/. I import an image

3/. When I deform it, its edges don't preserve their aspect.

Is there a place where we can modify/specify the slices?

Thanks a lot for the help. ^^

Hi. It's located in the object's Properties panel, as specified in the manual...

construct.net/en/make-games/manuals/construct-3/plugin-reference/9-patch

Thanks for the help it's really helpfull. ^^