In p:IGI+, at the minute, there are two origins of a data model. For all software customers, there is access to application models; these models, on creation, are stored in the Artefact Manager in parent blue folders.
Then, for our ML partnership customers, there is access to the online ML model toolbox. The models created through this route (right-click on a page >> Create Model >> Machine Learning…) are stored, viewed and managed through the Model Manager (Model >> Open Model manager…)
Seeing a white empty box when you open the Model Manager indicates that the project at present does not have any models created via the Machine learning model toolbox. Models listed in the Artefact manager are application-created Models.