To delete a table in the diagram:

  1. Right-click on the table header part of the table and select Delete table.
  2. Click Yes to confirm the delete.

The selected table and all of its associated foreign key joins are deleted.

As Source Models try to accurately represent the source, they do not, by default, allow tables to be deleted. To change this, go to Tools > Settings > Category > Creation and select the Manual checkbox for Entity. It would be better however to add a model of a different type; one that allows tables to be deleted; and to import the diagram from the source model into the new model. You will then be able to delete the required table.