Layers are a really cool and powerful feature of Construct 2. There are just two small things I miss that would make them even easier to use:
1) Unique layer IDs
Currently, layer IDs are more like a sort order, as they're based on the layer order. This makes it tricky to use them to identify layers (for example, when creating new objects through events) because as soon as you add a new layer, the layer IDs change. What I miss is either a constant numeric layer ID that doesn't change based on ordering, or the possibility to add your own custom identifier to a layer. You can use variables to store your layer IDs, but you still have to update them manually everytime you add/delete/reorder layers which is quite cumbersome.
The easiest solution might be to implement some kind of "lock layer ID" checkbox on layers, so that IDs stop changing based on sort order and instead just auto-increment. Or an editable textbox called "Identifyer" underneath the layer name in the layer settings, that can then be used instead of layer ID in events to identify layers. This should be both back- and forward compatible.
2) The ability to select objects from the Z order list
We already have the "Z order" window, which is awesome. However, currently you can only "Flash this instance" and not really select objects using this window. If you could select them just by clicking on them in the list, that would be very useful when you have many small objects on a layer that are hard to find and click on using the normal view.
I also think the current filter in the Z order window is a bit too smart for me, as it hides objects that are not overlapping an object when it's selected. Although it's an impressive feature, it would be great if you could disable this feature, to always show all objects on the active layer, even if an object is selected. Maybe this could be changed at the same place you choose "Show active layer only" (which I prefer to leave on).
Sorry if these ideas have been mentioned before, or you already have them in your todo. Love the new beta versions, and your focus on tilemap and multiplayer support. Keep up the great work!