It's potentially confusing that these APIs differ:
Naming: addClassesProvider() vs. addClassProvider()
The working set class provider can return null/undefined, while it's unclear if the project tree one can (though it can return "")
The project tree icon provider can return a React.DOM.ins but the working set one cannot
The project tree icon provider docs say it can return a raw DOM object, but the working set docs don't list this as allowed (I think it may work anyway though?)
The working set icon provider docs say it can return undefined, but the project tree docs don't list this as allowed (and it appears that it would crash)
It's potentially confusing that these APIs differ:
addClassesProvider()
vs.addClassProvider()
""
)React.DOM.ins
but the working set one cannot