I have a requirement to add a button in ShellHeaderToolbar in the MainShell. I tried adding a button but was not successful as ShellHeaderToolbar is not of container type. Is there any workaround for this?
I did this in my Recently Viewed Records add-on in the marketplace, it wasn't easy and took a bit of a hack. You'll need to override the MainShell and what I ended up doing is add a button into the shell that I move at runtime into the ShellHeaderToolbar. Feel free to look at the source of that add-on to see what I am doing to accomplish this. Ideally, it would be great if that were a container and you could add items to it, but sadly not the case.