A Mendix 5 compatible version of the widget, with both the TreeView and the GridView in the package, and support for microflow datasources has been released in the AppStore as version 3.0.
The "TreeView and GridView" widget in the appstore is marked as being mx5 compatible. Have you tried upgrading to the latest version of that widget, and then overwriting the tree view with the one you mentioned?
*Edit: If that doesn't work, please file a support request to have the problems with the widget fixed.