Bug 31683 Show In doesn't work for class file in rt.jar
I20030611 - create Test project that uses Jar container - open NumberFormat.class - activate Show In... and choose Package Explorer Observe: NumberFormat.class doesn't get revealed.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
/**
	 * An editor has been activated.  Set the selection in this Packages Viewer
	 * to be the editor's input, if linking is enabled.
	 */
	void editorActivated(IEditorPart editor) {
		if (!isLinkingEnabled())  
			return;
		showInput(getElementOfInput(editor.getEditorInput()));
	}
	boolean showInput(Object input) {
		Object element= null;
			
		if (input instanceof IFile && isOnClassPath((IFile)input)) {
			element= JavaCore.create((IFile)input);
		}
				
		if (element == null) 
			element= input;
				
		if (element != null) {
			ISelection newSelection= new StructuredSelection(element);
			if (!fViewer.getSelection().equals(newSelection)) {
				try {
					fViewer.removeSelectionChangedListener(fSelectionListener);						
					fViewer.setSelection(newSelection);
	
					while (element != null && fViewer.getSelection().isEmpty()) {
						
						element= getParent(element);
						if (element != null) {