Bug 9159 Classpath wizard should not complain when adding missing source folder
Build 20020125 - Define a project A with source folder 'src1'. - Go to the .classpath file and edit it to insert one extra line: <classpathentry kind="src" path="src2"/> below the line referring to first source folder: <classpathentry kind="src" path="src1"/>. - Now, try to add this missing source folder 'src2', it isn't allowed by the wizard, one has to add a basic folder instead. Note: It is not such an uncommon scenario, the classpath modification could simply occur by catching up with a shared classpath having one more source folder on it, and which is locally missing.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/BuildPathsBlock.java
IWorkbench workbench= JavaPlugin.getDefault().getWorkbench();	
		Image projectImage= workbench.getSharedImages().getImage(ISharedImages.IMG_OBJ_PROJECT);
		
		fProjectsPage= new ProjectsWorkbookPage(fClassPathList);		
		item= new TabItem(folder, SWT.NONE);
		item.setText(NewWizardMessages.getString("BuildPathsBlock.tab.projects")); 
		item.setImage(projectImage);
		item.setData(fProjectsPage);
		item.setControl(fProjectsPage.getControl(folder));
		
		fLibrariesPage= new LibrariesWorkbookPage(fWorkspaceRoot, fClassPathList);		
		item= new TabItem(folder, SWT.NONE);
		item.setText(NewWizardMessages.getString("BuildPathsBlock.tab.libraries")); 
		item.setImage(imageRegistry.get(JavaPluginImages.IMG_OBJS_LIBRARY));
		item.setData(fLibrariesPage);
		item.setControl(fLibrariesPage.getControl(folder));
		
		
		Image cpoImage= JavaPluginImages.DESC_TOOL_CLASSPATH_ORDER.createImage();
		composite.addDisposeListener(new ImageDisposer(cpoImage));	
		
		ClasspathOrderingWorkbookPage ordpage= new ClasspathOrderingWorkbookPage(fClassPathList);		
		item= new TabItem(folder, SWT.NONE);
		item.setText(NewWizardMessages.getString("BuildPathsBlock.tab.order")); 
		item.setImage(cpoImage);
		item.setData(ordpage);
		item.setControl(ordpage.getControl(folder));
				
		if (fCurrJProject != null) {
			fSourceContainerPage.init(fCurrJProject);