Of the past. Currently, it is, because some interfaces are much like a web/mobile counterpart. So there’s a “burguer” button somewhere and the bar pops up or hides pressing it.
In WinUI 3, such kind of sidebar control is called NavigationView
Still not common. They are bad UI design choices that we have to suffer on mobile because there just isn’t enough horizontal space. They hide options that should be more discoverable. There is no good reason to use one on desktop. The WinUI NavigationView is closer to a source list, just with a narrow display mode. It doesn’t hide completely, so it’s not really the same thing. But we’re splitting hairs.
It’d just surprise me if Xojo were to add something that no desktop project should need before adding one that even their own IDE uses. Source lists are common. Apple Mail, Music, Finder, Photos, Windows Explorer, Settings, and Mail.
If you want an “offcanvas” you use a container control. My app used to use a design like that. It was a bad design. If you want a source list, you customize the hell out of a list box.
But anyway, we just don’t know what Xojo has planned for that. Names are funny. Maybe sidebar means source list. Maybe sidebar means offcanvas. Maybe it means something else entirely.
We’re trying to work in sync as much as possible. Unless something unexpected happens, Popovers will appear in Desktop and Web at the same time. The same will happen with Sidebars, I’ll ask to update the Roadmap.
Sidebar for web is a critical feature that will make XOJO Web 2.0 complete.
Currently , you either have to roll up one on your own or buy the commercial plugins.
The lack of inherent capability to provide side menus via sidebar cripples XOJO Web application.
Let the critical features be all provided by XOJO.
The extra ones can be provided by commercial plug-ins.