Bug 32224 [Show In]Back-linking doesn't work for .class files in jars
Build 20030218 1. Enable back-linking in Package Explorer 2. Open Object (in rt.jar) Observe: An editor on Object.class opens (it shows the attached source). However Object.class is not shown in Package Explorer Note that Alt-Shift-s->Package Explorer doesn't work either.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
element= JavaCore.create((IFile)input);
				
		if (element == null) 
			element= input;
				
		if (element != null) {
			
			
			IStructuredSelection oldSelection= (IStructuredSelection)getSelection();
			if (oldSelection.size() == 1) {
				Object o= oldSelection.getFirstElement();
				if (o instanceof IJavaElement) {
					ICompilationUnit cu= (ICompilationUnit)((IJavaElement)o).getAncestor(IJavaElement.COMPILATION_UNIT);
					if (cu != null) {
						if (cu.isWorkingCopy())
							cu= (ICompilationUnit)cu.getOriginalElement();
						if ( element.equals(cu))
							return false;
					}
	
					IClassFile cf= (IClassFile)((IJavaElement)o).getAncestor(IJavaElement.CLASS_FILE);
					if (cf != null && element.equals(cf))
						return false;
				}
			}
			ISelection newSelection= new StructuredSelection(element);
			if (!fViewer.getSelection().equals(newSelection)) {
				try {
					fViewer.removeSelectionChangedListener(fSelectionListener);						
					fViewer.setSelection(newSelection);