FULL PRODUCT VERSION :
JRE6 early access (jre6u10b08)

ADDITIONAL OS VERSION INFORMATION :
Windows XP SP2

A DESCRIPTION OF THE PROBLEM :
According to the Nimbus spec, when a JTree cell is selected, the little triangle used to expand/collapse parents should be drawn in white instead of the normal gray color. Instead, it's always drawn in the same gray color regardless of selection state, which is not easy to see against the blue background of the selection.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Use Nimbus.
2. Create a JTree with anything in it.
3. Select a parent node.
4. Bear witness that the little gray triangle on the left hand side, used to expand/collapse the parent, is not being shown as white.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected a white triangle, per the Nimbus spec for trees.
ACTUAL -
Got the same gray triangle that's used for non-selected tree parents.

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
No workaround available as far as I know.