Strange Errors, Probably the Bugs of the .net Framework

Question

I Found two Very Strange Errors in my Program 1) The MDI Child Cannot Maximize itself sometimes, but the Right Top Corner of the MDI Child has the button of "RESTORE" ( as Restore button only occurs when the Screen is maximized) Please referred to the picture -- http://novasolution.net/Error1.jpg Way to make it occurs: Start up the Program -> Click the Shipment Icon, Click the Flight Icon, Click the Shipment Icon, Click the Flight Icon -> After all the above, when I click the Shipment Icon again, the Shipment Page cannot maximize itself as shown in the picture. 2) The MDI Parent has two or more sets of "minimize-restore-close" button on the right-top corner. Please referred to the picture -- http://novasolution.net/Error2.jpg and http://novasolution.net/Error2-2.jpg Way to make it occurs: Do the steps in Error one, and then close the Shipment Page and start another Shipment Page can "duplicate" another one of "minimize-restore-close" button. are these errors belonging to the Framework bugs? and how can I solve it??? Please HELP~~~!! THANKS!!!