Bug 76439 Classfile editor: Allow source attachment option for classes in class folders
20041017 When you open a class file for a class folder that has no source attchment you see a message 'No source available...' but no button that brings you to the source attachment page like it is done for JARs. ClassfileEditor line 225 is too restrictive, the test .isArchive() seems to be too much
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/ClassFileEditor.java
button= createButton(composite, JavaEditorMessages.getString("SourceAttachmentForm.button.changeAttachedSource")); 
				}
				button.addSelectionListener(getButtonListener(entry, containerPath, jproject));
			}
			
			private SelectionListener getButtonListener(final IClasspathEntry entry, final IPath containerPath, final IJavaProject jproject) {
				return new SelectionListener() {
					public void widgetSelected(SelectionEvent event) {				
						try {
							Shell shell= fScrolledComposite.getShell();
							IClasspathEntry result= BuildPathDialogAccess.configureSourceAttachment(shell, entry);
							if (result != null) {
								applySourceAttachment(shell, result, jproject, containerPath);
								verifyInput(getEditorInput());
							}
	
						} catch (CoreException e) {
							String title= JavaEditorMessages.getString("SourceAttachmentForm.error.title"); 
							String message= JavaEditorMessages.getString("SourceAttachmentForm.error.message"); 
							ExceptionHandler.handle(e, fScrolledComposite.getShell(), title, message);				
						}
					}
	
					public void widgetDefaultSelected(SelectionEvent e) {}
				};
			}
			
			protected void applySourceAttachment(Shell shell, IClasspathEntry newEntry, IJavaProject project, IPath containerPath) {
				try {
					IRunnableWithProgress runnable= SourceAttachmentBlock.getRunnable(shell, newEntry, project, containerPath);