title: Process files crash unexpectedly
body: <p>I am working on a project in Drools6. I have defined a few custom tasks using workitemhandler. When I create a new process file(*.bpmn file) and model it by adding my custom tasks and other inbuilt blocks, everything works fine in the beginning. But, if the complexity of the .bpmn flow diagram increase i.e, I add about 4-5 custom tasks, create sub-processes, add a few gateways etc, the program crashes and I will not be able to open my flow diagram again. It says there is a parse error. </p>
  
  <p>I have tried reinstalling eclipse, but it still gives me the same error. I have not used exception handling in the java class of my custom tasks. Could this be why my program is crashing. </p>
  
  <p>please guys, if anyone has come across a similar issue, let me know how you resolved it.</p>
  
  <p>Thank you    </p>