Currently, the whole document is kept in memory. In some cases, this creates too much of a memory footprint (even exceeding the usable ~1.2 GB of a .NET process) and causes an OutOfMemoryException. For example, a document with around 2000 pages will fail on import. 



Optimize how style properties are used. Default style properties could be shared among all elements of the same type who does not have any local values.