The JTable column header's height is more in Window LAF on Windows Vista.
To reproduce this:
1. Run the attached sample
2. Choose the Windows LAF in the combox box
Now you can see the Column Header's height is more than what it supposed to be. When you compare with the native, the height is twice as normal height.
java version "1.6.0-beta2"
Java(TM) SE Runtime Environment (build 1.6.0-beta2-b82)
Java HotSpot(TM) Client VM (build 1.6.0-beta2-b82, mixed mode, sharing)