Performance Issues with Large Documents
Problem
The performance of the application slows down considerably over time when editing large documents.
Solution
A possible cause is that the application needs more memory to run properly. 
               You can increase the maximum
                  amount of memory available to Oxygen XML Author plugin by setting the
                  -vmargs and -Xmx parameters in the command used to
                  launch the Eclipse platform.
               
            
Attention
The maximum amount of memory should not be equal to the physical amount
                  of memory available on the machine because in that case the operating system and other
                  applications will have no memory available.
               
            