Bug 6672 jar no longer exported after attach source
1206 1. Create a project test. 2. Add a jar (say resources.jar) to the classpath and export the entry 3. Attach source (say resourcessrc.zip) to the jar. Notice, the jar is no longer exported - this information is discarded during the attach source process.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
ElementTreeSelectionDialog dialog= new ElementTreeSelectionDialog(getShell(), lp, cp);
		dialog.setAllowMultiple(false);
		dialog.setValidator(validator);
		dialog.addFilter(filter);
		dialog.setTitle(NewWizardMessages.getString("SourceAttachmentBlock.intjardialog.title")); 
		dialog.setMessage(NewWizardMessages.getString("SourceAttachmentBlock.intjardialog.message")); 
		dialog.setInput(fRoot);
		dialog.setInitialSelection(initSel);
		if (dialog.open() == dialog.OK) {
			IFile file= (IFile) dialog.getFirstResult();
			return file.getFullPath();
		}
		return null;
	}
	
	/*
	 * Opens a dialog to choose path in a zip file.
	 */		
	private IPath choosePrefix() {
		if (fResolvedFile != null) {
			IPath currPath= new Path(fPrefixField.getText());
			String initSelection= null;
			if (fIsVariableEntry) {
				IPath resolvedPath= getResolvedPath(currPath);
				if (resolvedPath != null) {
					initSelection= resolvedPath.toString();
				}
			} else {
				initSelection= currPath.toString();
			}