Infinite loop on File > Open...

[stevevestal]

When I do File > Open... on the attached file (original name extension ".owl", I changed it to ".txt" so I could drag-and-drop to this issue), Protege 5.2.0 on Windows 10 hangs. The task manager says CPU usage is very high, so I assume it is an infinite loop. I have to end the JVM in the task manager. Is there something wrong with this ontology? Still, it shouldn't get into an infinite loop. (This file was generated using Apache Jena, but I created it using that API, so it might be improper in some way.)

fhowl_vocab.txt