9-Slice-Scaling not working

[coldscooter]

I have a checkbox component that I'm trying to prevent the box itself from scaling when using the free transform tool.

I have 9-slice-scaling enabled in the component properties:

 

In the component itself I've moved the guide lines as so:

However when I scale the component on the stage and publish, it looks like this (it's squashed):

Anyone know what I'm doing wrong here?

Thanks