Currently Being ModeratedJan 30, 2013 10:39 AM (in response to Tapita Costa Rica)
That is the way is is supposed to work. Your MBP does not supply enough power to charge the battery efficiently. It may be charging, but at a trickle rate and it will show as not charging. That is why a power adapter is included with the iPad. Use it.
Read more about charging the battery here.