FULL PRODUCT VERSION :
Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.

C:\Users\Owner>java -version
java version "1.8.0_71"
Java(TM) SE Runtime Environment (build 1.8.0_71-b15)
Java HotSpot(TM) Client VM (build 25.71-b15, mixed mode)

C:\Users\Owner>

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.

C:\Users\Owner>ver

Microsoft Windows [Version 6.3.9600]

C:\Users\Owner>

A DESCRIPTION OF THE PROBLEM :
This is mainly and primarily an issue with the Windows look and feel not being consistent. However, the other look and feels could also mimic this as the default themes in the Qt Framework do.

When a JInternalFrame is maximized it does not remove its border and title bar buttons under the Windows look and feel. In Windows Forms the border is removed and a menu bar is created with the icon of the MDI window added to the far left and unique close buttons added to the far right of the menubar. Note that if the frame already has a menubar then it will be used instead. Testing with Visual Studio produces the following results.
http://i.imgur.com/aTn2SjC.png

It is important to mention that some Linux distributions such as Ubuntu that use GNOME will have the menu bar moved to the native menu bar if the setting is enabled in Swing. This had to be patched previously in the Qt Framework as well, care should be taken to mimic the native functionality of GTK and Linux applications with MDI's.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
One would expect the borders to be removed at least in the native Windows look and feel if not the others too.
ACTUAL -
The border is not removed and the style is inconsistent with native Windows Forms.

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
A work around requires deriving a custom WinInternalFrameUI and removing the borders. Also requires hacking the title buttons onto the menu bar.

SUPPORT :
YES