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
private JavaModelException probeInputForSource(IEditorInput input) {
		if (input == null)
			return null;
		IClassFileEditorInput classFileEditorInput= (IClassFileEditorInput) input;
		IClassFile file= classFileEditorInput.getClassFile();
			
		try {
			file.getSourceRange();
		} catch (JavaModelException e) {
			return e;			
		}
		return null;
	}
	/**
	 * Checks if the class file input has no source attached. If so, a source attachment form is shown.
	 */
	private void verifyInput(IEditorInput input) throws CoreException {
		if (fParent == null || input == null)
			return;
		IClassFileEditorInput classFileEditorInput= (IClassFileEditorInput) input;
		IClassFile file= classFileEditorInput.getClassFile();
		
		
		if (file.getSourceRange() == null) {
			
			if (fSourceAttachmentForm != null)
				fSourceAttachmentForm.dispose();
			SourceAttachmentForm form= new SourceAttachmentForm(file);
			fSourceAttachmentForm= form.createControl(fParent);
			fStackLayout.topControl= fSourceAttachmentForm;