Show In sources which need to provide additional entries to the Show In list of targets
can provide this interface.
The part can either directly implement this interface, or provide it
via IAdaptable.getAdapter(IShowInTargetList).
See Also:IShowInSource See Also:IShowInTarget since: 2.1
Returns the identifiers for the target parts to show.
The target parts must be Show In targets.
the identifiers for the target parts to show See Also:IShowInTarget