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
PixelConverter converter= new PixelConverter(parent);
		
		Composite composite= new Composite(parent, SWT.NONE);	
		
		GridLayout layout= new GridLayout();
		layout.marginWidth= 0;
		layout.numColumns= 1;		
		composite.setLayout(layout);
		
		TabFolder folder= new TabFolder(composite, SWT.NONE);
		folder.setLayout(new TabFolderLayout());	
		folder.setLayoutData(new GridData(GridData.FILL_BOTH));
		folder.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				tabChanged(e.item);
			}	
		});
		
		ImageRegistry imageRegistry= JavaPlugin.getDefault().getImageRegistry();
		
		TabItem item;
				
		fSourceContainerPage= new SourceContainerWorkbookPage(fWorkspaceRoot, fClassPathList, fBuildPathDialogField);		
		item= new TabItem(folder, SWT.NONE);
		item.setText(NewWizardMessages.getString("BuildPathsBlock.tab.source")); 
		item.setImage(imageRegistry.get(JavaPluginImages.IMG_OBJS_PACKFRAG_ROOT));
		item.setData(fSourceContainerPage);		
		item.setControl(fSourceContainerPage.getControl(folder));