In version 4.1.3 if I select a models relational model in the browser and right click and select delete, a new blank relational model is created (normally) which I can then engineer to. However although the old relational design is deleted from the projects rel folder and a new folder is created inside the rel folder, no matching .xml file for this new folder is created. As a consequence when I reopen the model the relational model 'disappears'. It is relatively easy to resurrect the relational model by copying in a .xml file from another models rel folder, changing the file name to match the folder name and updating the id on the 2nd line of the file.
Has anyone else come across this or is it a known bug?