Fix message.
Set the related nodes only once.

The method was invoked twice. This means that the annotation
were loaded twice.
Refactor code to reduced the number of calls.
Refactor code to limit number of calls.
Add doc.
Load the annotation only once.

When selected the node (displayed in tree), the annotations
were loaded twice.
Load only once the annotation.
Fire property only once.

This could lead to out of memory exception due to the
number of call.
Remove System.err and update header.
Only load data once when deselecting from central panel

Issue occurred when deselecting from central panel using the
table view.
Use multimaps instead of map
Add missing javadoc.
Capitalize.
Move imports.
Capitalize
Check emptiness.
Merge pull request #2469 from jburel/large-selection

Large selection