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
NewWizardMessages.getString("BuildPathsBlock.classpath.up.button"), 
			 NewWizardMessages.getString("BuildPathsBlock.classpath.down.button"), 
			 null,
			 NewWizardMessages.getString("BuildPathsBlock.classpath.checkall.button"), 
			 NewWizardMessages.getString("BuildPathsBlock.classpath.uncheckall.button") 
		
		};
		
		fClassPathList= new CheckedListDialogField(null, buttonLabels, new CPListLabelProvider());
		fClassPathList.setDialogFieldListener(adapter);
		fClassPathList.setLabelText(NewWizardMessages.getString("BuildPathsBlock.classpath.label"));  
		fClassPathList.setUpButtonIndex(0);
		fClassPathList.setDownButtonIndex(1);
		fClassPathList.setCheckAllButtonIndex(3);
		fClassPathList.setUncheckAllButtonIndex(4);		
			
		fBuildPathDialogField= new StringButtonDialogField(adapter);
		fBuildPathDialogField.setButtonLabel(NewWizardMessages.getString("BuildPathsBlock.buildpath.button")); 
		fBuildPathDialogField.setDialogFieldListener(adapter);
		fBuildPathDialogField.setLabelText(NewWizardMessages.getString("BuildPathsBlock.buildpath.label")); 
		fBuildPathStatus= new StatusInfo();
		fClassPathStatus= new StatusInfo();
		
		fCurrJProject= null;
	}
	
	
	
	public Control createControl(Composite parent) {
		fSWTWidget= parent;