Bug 25845 Support for manually attaching source to a class path container
From Dejan: There is a work item on the ability to manually attach source to classpath entries managed by classpath container. We discussed it and we have workable options but we would like if we can have it by M3 because we want to start self-hosting using classpath containers ourselves.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
IPath returnPath= new Path(result.getPath()).makeAbsolute();
				return modifyPath(returnPath, currVariable);
			}
		} else {
			
			if (ArchiveFileFilter.isArchivePath(currPath)) {
				currPath= currPath.removeLastSegments(1);
			}
		
			FileDialog dialog= new FileDialog(getShell());
			dialog.setText(NewWizardMessages.getString("SourceAttachmentBlock.extjardialog.text")); 
			dialog.setFilterExtensions(new String[] {"*.jar;*.zip"}); 
			dialog.setFilterPath(currPath.toOSString());
			String res= dialog.open();
			if (res != null) {
				return new Path(res).makeAbsolute();
			}
		}
		return null;
	}
	/*
	 * Opens a dialog to choose an internal jar.
	 */	
	private IPath chooseInternalJarFile() {
		String initSelection= fFileNameField.getText();
		
		Class[] acceptedClasses= new Class[] { IFolder.class, IFile.class };
		TypedElementSelectionValidator validator= new TypedElementSelectionValidator(acceptedClasses, false);
	
		ViewerFilter filter= new ArchiveFileFilter(null, false);