FULL PRODUCT VERSION :
java version "1.6.0_05-ea"
Java(TM) SE Runtime Environment (build 1.6.0_05-ea-b04)
Java HotSpot(TM) Client VM (build 1.6.0_05-ea-b04, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Windows XP

A DESCRIPTION OF THE PROBLEM :
In Nimbus, component tooltips have a thin gray outline on the top and right sections, but there's no outline in the bottom and left sections.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Set the tooltip text in any visual component and move the mouse over component and you will notice the absence of outlines in the bottom and left sections.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Having outlines shown in the bottom and left sections, or no outlines shown in the top and right sections.
ACTUAL -
No outlines shown in the bottom and left sections.

REPRODUCIBILITY :
This bug can be reproduced always.