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_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, 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 :
When using the native look and feel under Windows the JInternalFrame has incorrect padding.

A Windows Forms .NET Example:
http://www.c-sharpcorner.com/UploadFile/manish1231/how-to-arrange-the-display-of-multiple-mdi-child-forms-in-C-Sharp/Images/4.gif

JInternalFrame with Swing:
http://i.stack.imgur.com/0IJ6f.png

If we look at the Swing version we can observe that the padding along the bottom of the internal frame is not appropriate. We can also observe that the close button is cut off by a few pixels and the padding is also not far enough from the right.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a JInternalFrame and enable the default look and feel then run the application on Windows 7, 8, or 10.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I would expect the padding to be the same padding used in the native MDI frames and for the close button to be properly positioned.
ACTUAL -
The padding is incorrect and the close button is cut off by a few pixels.

REPRODUCIBILITY :
This bug can be reproduced always.

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Not applicable
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CUSTOMER SUBMITTED WORKAROUND :
The only current work around is to subclass the internal frame look and feel class and then correct the issues manually.

SUPPORT :
YES