So how do I tell what objects are on what layers, since you've got rid of that?
i don't know how it's different since i just now downloaded Construct, but you can select what layer you're working in on the right -- look for the small tab. you can click the little thumb-tack icon to get it to stay there.
[on a somewhat related note, there's an annoying behavior when you create another layer below (the down-pointing icon): it will change the ID of your other layers to higher numbers. this wouldn't be a big deal and it makes sense, but you need to go back and edit all the references to layers (like when you spawn an object). it would be nice if adding a layer below would automatically change the events that reference layers, so that they still spawn objects to the right layer.