When we click on default selected tab, the focus is not traversed to this tab and focus border is not shown. Click on some other tab in the same JTabbedPane and focus is transferred. On further clicks the focus traversal takes place.

Compile and run JTabbedPaneFocusTest
Click on tabs "LEFT 0", "BOTTOM 0", "RIGHT 0".
If focus is not getting traversed to this tab and no focus border is drawn bug is reproduced.