Possible UIMA Annotation Editor memory leak

**Describe the bug**
When opening and closing a CAS with UIMA Annotation Editor in eclipse, the memory consumption keeps piling up, even if running GC.

**To Reproduce**
Open big CAS, close it, run GC, observe memory.

**Expected behavior**
No memory leak.

**Please complete the following information:**
- OS: Linux

Start by reproducing the leak in the UIMA Annotation Editor with a large CAS on Linux, closing it and running GC while observing memory. Trace the editor's CAS open and close lifecycle to identify retained objects; done means repeated open/close cycles no longer show memory accumulating after GC.

Written by the indexing model from the issue text.