Bug 28510 java build path inconsistency [build path]
20021216 select rt.jar in the package explorer open properties it allows you to set the javadoc location but for source attachment you are sent somewhere else it's inconsistent - on the java build path they both look sort of the same (they sit under the same node in the tree)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/BuildPathsBlock.java
* Validates output location & build path.
	 */	
	private void updateOutputLocationStatus() {
		fOutputLocationPath= null;
		
		String text= fBuildPathDialogField.getText();
		if ("".equals(text)) { 
			fOutputFolderStatus.setError(NewWizardMessages.getString("BuildPathsBlock.error.EnterBuildPath")); 
			return;
		}
		IPath path= getOutputLocation();
		fOutputLocationPath= path;
		
		IResource res= fWorkspaceRoot.findMember(path);
		if (res != null) {
			
			if (res.getType() == IResource.FILE) {
				fOutputFolderStatus.setError(NewWizardMessages.getString("BuildPathsBlock.error.InvalidBuildPath")); 
				return;
			}
		}	
		fOutputFolderStatus.setOK();
		updateBuildPathStatus();
	}
		
	private void updateBuildPathStatus() {
		List elements= fClassPathList.getElements();
		IClasspathEntry[] entries= new IClasspathEntry[elements.size()];
	
		for (int i= elements.size()-1 ; i >= 0 ; i--) {