Your first picture does say that your "Parent Theme" (not default) theme is Amsport 5. It just means that in the first instance it will look for theme overrides in your activate theme and if they don't exist it will "fallback" to Amsport5. Amsport 5's parent theme is "Magento Blank".
Your second image confirms that your current activated theme is Amsport 2.
When you say the megamenu is not working what do you mean. Is it a module you are using?