sclass JExtendedTabbedPane >
//return (horizontalStrut 0) getMinimumSize

tabs <- jtabs "1" (horizontalStrut 0) "2" (horizontalStrut 0)
scp <- setBackground (Color green) (scp (jcenteredlabel "Content"))

onTabSelectedAndNow tabs (IVF1 idx -> scp set (jcenteredlabel (str idx)))

northAndCenter (centerAndEastWithMargin tabs (jcheckbox)) scp