Activiti Designer plugin hangs when printing a simple diagram

[micwic1]

I just installed Activiti Designer   (Activiti Eclipse BPMN 2.0 Designer 5.18.0.201508100929) in my Spring Tools Suite Eclipse IDE (Spring Tool Suite Version: 3.7.2.RELEASE Build Id: 201511261048 Platform: Eclipse Mars.1 (4.5.1))

The diagram window hangs after printing a very simple diagram.
The main window title bar still active and I need to close it (that cause eclipse to close completely).

[micwic1]

I just upgraded to the last STS version (Version: 3.7.3.RELEASE Build Id: 201602250940 Platform: Eclipse Mars.2 (4.5.2)) that solved this problem.