Memory leak when deleting a document

To reproduce (and see it):

• Start a java profiler (yourkit)
• Connect to your running CMS
• Open the memory view (with class list) and filter to include the following classes:

org.hippoecm.repository.impl.DocumentManagerImpl
org.hippoecm.repository.impl.WorkflowManagerImpl

• Log in to the CMS. The number of objects for the classes mentioned above increases by one.
• Open, then delete a document
• Log out
• In the profiler, force garbage collection a few times

Expected behavior: The number of objects for the classes mentioned above decreases by one.
Actual behavior: The number of objects for the classes mentioned above doesn't decrease.

This only seems to occur when deleting a document. When publishing, taking offline, moving, renaming or copying a document, no memory leak is observed.
Doing the logging in, deleting and logging out about 300+ times, brings your memory usage up to almost 500MB.