Bug 29755 Attach source does not allow one to select a folder... [build path]
When opening some .class that does not yet have a source attachment eclipse shows a text version of the interface defintion and a button for Attaching source. When pressing this button a window appaer where one can enter the name/location of a folder, zip or jar for the source. There are also a button for choosing it via a file selection dialog and this works fine for zip and jar files - but not for selecting a directory :( Workaround is just to enter the directory manually.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
* @deprecated 
	 */
	public SourceAttachmentBlock(IWorkspaceRoot root, IStatusChangeListener context, IClasspathEntry oldEntry) {
		this(context, oldEntry, null, null);
	}	
	
	/**
	 * @param context listeners for status updates
	 * @param entryToEdit The entry to edit
	 * @param containerPath Path of the container that contains the given entry or
	 * <code>null</code> if the entry does not belong to a container.
	 * @param project Project to which the entry belongs. Can be
	 * <code>null</code> if <code>getRunnable</code> is not run and the entry
	 * does not belong to a container.
	 *
	 */
	public SourceAttachmentBlock(IStatusChangeListener context, IClasspathEntry entry, IPath containerPath, IJavaProject project) {
		Assert.isNotNull(entry);
		
		fContext= context;
		fEntry= entry;
		fContainerPath= containerPath;
		fProject= project;
		
		int kind= entry.getEntryKind();
		Assert.isTrue(kind == IClasspathEntry.CPE_LIBRARY || kind == IClasspathEntry.CPE_VARIABLE);
				
		fWorkspaceRoot= ResourcesPlugin.getWorkspace().getRoot();
		
		fNameStatus= new StatusInfo();