I would like to reopen this ticket as it seems to be broken again after upgrading to Angular 9. I have several StackBlitz repos, but can't get the Angular 9.0.2 one to load.
The following work:
When trying to upgrade the last one to Angular 9 it tells me I need to add tslib dependency. I do, but then the toolbar buttons disappear.
Note this is only when trying to create a reproduction for you in StackBlitz.
In my own code, I don't have to add tslib and the toolbar draws just fine. However, when toggling the button's disabled, it doesn't work. The button is always disabled.