Bug 68011 [java search] "Search the JRE System Libraries" looks like a local preference but behaves as a global one... [search]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/FindReferencesAction.java
* Note: This constructor is for internal use only. Clients should not call this constructor.
	 * @param editor the Java editor
	 */
	public FindReferencesAction(JavaEditor editor) {
		super(editor);
	}
	
	Class[] getValidTypes() {
		return new Class[] { ICompilationUnit.class, IType.class, IMethod.class, IField.class, IPackageDeclaration.class, IImportDeclaration.class, IPackageFragment.class, ILocalVariable.class, ITypeParameter.class };
	}
	
	void init() {
		setText(SearchMessages.Search_FindReferencesAction_label); 
		setToolTipText(SearchMessages.Search_FindReferencesAction_tooltip); 
		setImageDescriptor(JavaPluginImages.DESC_OBJS_SEARCH_REF);
		PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IJavaHelpContextIds.FIND_REFERENCES_IN_WORKSPACE_ACTION);
	}
	int getLimitTo() {
		return IJavaSearchConstants.REFERENCES;
	}	
	
	IJavaSearchScope getScope(IJavaElement element) throws JavaModelException {
		return JavaSearchScopeFactory.getInstance().createWorkspaceScope(JavaSearchPage.getSearchJRE());
	}
	public void run(IJavaElement element) {
		SearchUtil.warnIfBinaryConstant(element, getShell());
		super.run(element);
	}
}