Hmmm Never have seen a digital site or app with a menu!!! really strange to make that available. Let's make a menu with all images of every possible outcome. Better to forget the program XD and make it for real to save time.

Yes! definitely will be need a overlay and popup menu and tools support

I would love to be able to define animations and interactions as symbols so I could reuse them / copy paste / etc

Totally need!

I agree with Dawson, the first thing I was trying to do in the demo was make the iOS UI on the top to be persistent whilst the canvas changed underneath. It would also be good to lock the position of menu hamburger icon etc.

I agree. This is pretty critical in order to generate dialogs and menus, etc. In other apps we've seen it where, like others said, you would do it in layers but the whole "dialog" could be a container that we would move around, much like how we could move a whole folder of items in Photoshop. Maybe layers/folders is the biggie that helps solve this.

The ability to layer images in top of each other. Like side menus and pop ups alerts works.

I think this could apply to so many use cases. Basically the ability to hide/show/animate one or more elements onto the art board instead of linking to an entirely separate board.

This would enable much faster prototyping because it wouldn't require duplicating the entire art board just to add one element (like an overlay).

Examples of good uses are Dialogs, Sidebars, notifications, Toggles (not only an overlay but the ability to toggle visibility of a group depending on the state of the toggle).

An Overlay animation would be beneficial to show things for example how a menu would work on mobile to overlay on half of the current content.

When adding dialogs, context menus, etc. it would be really valuable to not have to duplicate the artboard to show the dialog. Would rather link to menu and show/hide it based on link/button click. Examples of use include modals, menus that slide in from left, droplists, context menus, etc.

This is an incredibly useful feature not just for lightbox but also web application features; modals, side panels and navigation features. Also alerts and notifications, hover tooltips and changing states of single components (colors, animations etc) that are specific to certain sections of an app, where changing out the whole page will not be applicable.

One approach would be to use layers for this purpose. Put transitional elements like menus, overlays, ghost notifications, etc. into layers and then interactively show/hide layers as required. Yes, please give us layers :)

We use overlays in a number of ways. They often get used for videos, question feedback, site wide login, etc

This feature is 100% required for me to use XD vs something like InVision. If I can't simulate menus or different states, XD is useless, unfortunately. Key uses:
-Menu drop-downs (though, a more elegant solution would be nice)
-Different states or revealed content
-Paired with an on-hover this could be used for a hover state (some of us are stuck in the web world with hover states! :P )
-Toggled content