if (!(component instanceof JCollapsiblePane)) {
// something wrong in this JTaskPaneGroup
return super.getPreferredSize(c);
}
JCollapsiblePane collapsible = (JCollapsiblePane)component;
Dimension dim = collapsible.getPreferredSize();
Border groupBorder = group.getBorder();
if (groupBorder instanceof PaneBorder) {
Dimension border = ((PaneBorder)groupBorder).getPreferredSize(group);
dim.width = Math.max(dim.width, border.width);