As for now, it's impossible to add a Form control into a Container control which makes it very difficult to manage Responsive designs with applications that uses Forms.
It should be possible to add a Form control into a Container control as it is possible with other controls.
I support this idea. This is bordering me for some time and I thought some time ago I posted an idea on this myself, probably forget to do so. Beïng based on React this shouldn't be a very difficult change, probably only needed to add the Form Component as a child for the container component.
@Anonymous and @Audrie-MSFT, could you invite the right colleagues into this thread. Thanks.
FYI, if you create the new form control then cut(ctrl+x) and paste(ctrl+v) it into a container control it seems to work just fine. May not be officially supported or intended but it gets the job done.