Spinner
The buttons are not aligned properly with the text Field
The arrows are larger than seen in the GTK look and feel
text is right aligned in Java while in Native it is left aligned.
Spinner text is selected when in focus in GTK Native
while in java it is not highlighted

Another noticed effect is the incremnet happening while pressing decrement arrow and vice versa

http://sqindia.india/disk11/swing/GTKFidelityResults/Solaris10/reports.b59.BluePrint/SpinnerTest.html

Difference in disabled spinner between native and java in Win L&F.

In native, the disabled spinner has light gray background inside the spinner but in java,the disabled spinner has white background inside the spinner.Becuase of that the java spinner looks like enabled spinner even if its disabled.

In java, the spinner background has not changed once disabled the spinner.Its disables only up & down buttons and text. But in native, the spinner background has changed once disabled the spinner.It disables the entire component including background.

Please check the below URL for looking difference between the native and java Windows L&F.

http://sqindia.india/export/disk11/swing/WindowsFidelityResults/b58/reports.WindowsClassic/SpinnerTest.html