You can't delete a project from the modeler. Just go to the project's directory, delete the files and folders for the project you want to delete. Open the modeler and try to open the deleted project and you will be asked if the project needs to be removed from the list. Be aware that when the project is connected to the team server this is not deleted! This can be deleted in the app platform website.
This can be deleted in the app platform website.
> Go to your Project > Choose Get Project ID > Go to Project Settings > Delete project.