I am slightly confused as to why the properties panel changes suddenly (as far as I know) when using shapes in Photoshop CC.
This is the normal properties panel when working with shapes
Then I sometimes get this
On the first image, I can see that I could toggle between the two views (masks and live shape). However On this second image I only see the mask tab. Is there a way to get the normal tab back. Or somehow prevent this from happening.
Generally this problem is linked to how Photoshop interprets a users intent. At some point you might have inadvertently selected a sub path of the live shape; this is usually done with the direct selection tool. What happens though is that even if you select a different layer, when you come back to the initial layer it still defaults to the sub path selection and the mask dialog box.
This is the usually the reason for the odd behavior of the property panel. To remedy this situation you have to reselect the shape with the path selection tool and you should see the normal default behavior and option for live shape at the top.
I don't want to steal the thunder, but this was first addressed here and can be explained in a little greater detail. http://forums.adobe.com/thread/1235457?start=0&tstart=0