FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
Ocurred in jdk 1.6.0_21 but seems to be inherent for me in jdk 1.8

BasicTabbedPaneUI does not take the tabAreaInsets into consideration, calculating the preferredTabAreaHeight/Width when getTabLayoutPolicy() == SCROLL_TAB_LAYOUT

Replacing BasicTabbedPaneUI.TabbedPaneScrollLayout

        protected int preferredTabAreaHeight(int tabPlacement, int width) {
            return calculateMaxTabHeight(tabPlacement);
        }

        protected int preferredTabAreaWidth(int tabPlacement, int height) {
            return calculateMaxTabWidth(tabPlacement);
        }

with

        protected int preferredTabAreaHeight(int tabPlacement, int width) {
            int maxTabHeight = calculateMaxTabHeight(tabPlacement);
            return calculateTabAreaHeight(tabPlacement, 1, maxTabHeight);
        }

        protected int preferredTabAreaWidth(int tabPlacement, int height) {
            int maxTabWidth = calculateMaxTabWidth(tabPlacement);
            return calculateTabAreaWidth(tabPlacement, 1, maxTabWidth);
        }

may fix this.


REPRODUCIBILITY :
This bug can be reproduced always.