FULL PRODUCT VERSION :
5.0-6.0

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
Scroll buttons on wrapped tabbed panes in RTL layout not showing. This is a bug in BasicTabbedPaneUI.TabbedPaneScrollLayout class (see below for a fix)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a tabbed pane in WRAP_TAB_LAYOUT mode with RTL orientation and a number of tabs. Under *all* core LAFs (Metal, Windows, Motif) the scroller buttons (on TOP and BOTTOM placement) are not showing.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Scroller buttons showing on the left-hand side of the tabbed pane on TOP and BOTTOM placement
ACTUAL -
No scroller buttons

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
The code from line 2756 as
                              case BOTTOM:
                              case TOP:
                              default:
                                int totalTabWidth = rects[tabCount-1].x + rects[tabCount-1].width;

                                if (totalTabWidth > tw) {
                                    visible = true;
                                    bx = (child == tabScroller.scrollForwardButton)?
                                        bounds.width - insets.left - bsize.width :
                                        bounds.width - insets.left - 2*bsize.width;
                                    by = (tabPlacement == TOP? ty + th - bsize.height : ty);
                                }

is correct only for LTR orientation. For RTL, it should check the rects[tabCount-1].x, and if it's negative, set visible to true and bx to either insets.left or insets.left + bsize.width.

This is impossible to do in custom LAF since almost everything (including the layout class) is private.