A small number of people have been seeing an error when using the BPMN process editor in JDeveloper 11.1.1.6 (PS5).  The symptom is a NullPointerException, as seen in the log, an example below, and a dialog box telling you an unexpected error has occurred (see image below).

If you hit this issue, you should log a service request with Oracle Support and ask for a patch for bug number 13088538.  You will need to provide details about your JDeveloper environment, versions of plugins, etc.

Performing action Save[ from oracle.bpm.fusion.studio.editor.ProcessEditor ]
 Invoking command: [ from oracle.bpm.fusion.studio.editor.ProcessEditor ]
 Performing action Rebuild BoundaryEvents.jpr[ from oracle.bpm.fusion.studio.editor.ProcessEditor ]
 Invoking command: modify adf-config for soa
 Invoking command: [ from oracle.bpm.fusion.studio.editor.ProcessEditor ]
 Invoking command:
 Invoking command:
 Invoking command:
 Invoking command:
 Uncaught exception
 java.lang.NullPointerException
   net.miginfocom.layout.Grid.addLinkIDs()
   net.miginfocom.layout.Grid.<init>()
   net.miginfocom.swing.MigLayout.checkCache()
   net.miginfocom.swing.MigLayout.getSizeImpl()
   net.miginfocom.swing.MigLayout.preferredLayoutSize()
   o.bpm.ui.layout.MigLayout.preferredLayoutSize(MigLayout.java:114)