Chart blocks are given limited height on the welcome and portal pages. If you want to show a chart on one of these pages you most likely want to show the whole chart.
This patch expands height to height required by the chart without a vertical scroll bar.
This patch was suggested by fisharebest in response to a help forum question.
DIff of rev 6500 of blocks/charts.php (current rev as of submit date):
< require $THEME_DIR.'templates/block_main_temp.php';
> require $THEME_DIR.'templates/block_small_temp.php';